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

Abstract

The present application relates to the field of agricultural environmental protection and groundwater pollution remediation technology, and particularly relates to a kind of agricultural non-point source groundwater pollution remediation technology screening system and method, system includes: barrier technology screening module, degradation technology screening module, removal technology screening module, cost accounting module;The barrier technology is quantitatively evaluated to the pollutant barrier capacity of farmland infiltration by soil hydraulics equation, the efficient degradation technology of aeration zone is screened using Fick's law and Monod kinetics model, and the economic feasibility of aquifer removal technology is verified based on shadow engineering method and full life cycle cost model;The method comprises: determining the optimal technology of farmland infiltration, aeration zone and aquifer link in turn through each module, and generating a feasible scheme in combination with cost accounting.Solve the problem that traditional technology has poor adaptability and high cost in agricultural scene, realize the whole chain accurate screening and economically feasible remediation technology combination from pollution source to end.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of agricultural environmental protection and groundwater pollution remediation, and particularly relates to an agricultural non-point source groundwater pollution remediation technology screening system and method. BACKGROUND

[0002] The remediation of agricultural non-point source groundwater pollution is a worldwide problem. When traditional industrial pollution remediation technology is directly applied to agricultural non-point source pollution, there are core defects such as high cost, large disturbance and non-sustainability. The root cause lies in the fact that the particularity of agricultural cultivation is not considered, and the frequent irrigation, fertilization and soil turning require the remediation technology to be compatible with farmland ecology, while the strong intervention characteristics of industrial technology lead to the incoordination with agricultural production.

[0003] Internationally, the governance of agricultural non-point source pollution has long relied on source control, but there is a lack of effective remediation means for contaminated groundwater. Traditional technology screening only focuses on technical effects and ignores the economic affordability of agricultural scenarios. The acceptable daily remediation cost of farmers is usually less than 2000 yuan per mu, while the cost of industrial-level remediation technology is generally more than 20000 yuan per mu, resulting in that remediation projects are difficult to land due to the lack of investment subject support.

[0004] Existing groundwater pollution remediation technology screening is mostly a scoring method, which cannot quantify the adaptability of the technology in each link, including remediation time, investment, energy consumption, technology maturity and secondary pollution, and is not suitable for the screening of agricultural non-point source pollution remediation technology.

[0005] Therefore, the present application is proposed. SUMMARY

[0006] In order to solve the above technical problems in the prior art, the present application provides an agricultural non-point source groundwater pollution remediation technology screening system and method, which solves the problem of inadaptation and high cost of the prior art, and can realize precise, economic and sustainable pollution remediation screening.

[0007] To achieve the above purpose, the technical scheme of the present application is as follows:

[0008] In a first aspect, an agricultural non-point source groundwater pollution remediation technology screening system comprises:

[0009] A barrier technology screening module is used to evaluate the barrier ability of the technology to the infiltration of pollutants from farmland by quantitative calculation, and to screen the technology compatible with farmland cultivation;

[0010] Degradation technology screening module: used for targeting the pollutant components with strong migration ability based on the results screened by the barrier technology screening module, and evaluating the degradation ability of the technology to the pollutants in the aeration zone through experimental simulation or empirical data, and screening the technology with high degradation efficiency and low environmental risk;

[0011] Removal technology screening module: used for comparing the removal efficiency of the technology to the pollutants in the aquifer by using shadow engineering algorithm based on the results screened by the degradation technology screening module, and screening the technology with high removal amount per unit time and controllable cost;

[0012] Cost accounting module: used for verifying the whole-cycle cost benefit and generating a feasible technology scheme based on the results screened by the degradation technology screening module.

[0013] Further, the barrier technology screening module comprises:

[0014] Permeability coefficient calculation unit: used for calculating the influence of different materials on the permeability coefficient of the pollutants based on the soil hydraulics equation;

[0015] Nitrogen fertilizer loss evaluation unit: used for calculating the nitrogen fertilizer loss reduction rate by a parameterized evaluation model;

[0016] Compatibility verification unit: used for evaluating the compatibility of the technology with farmland tillage based on a soil physical property change model.

[0017] Further, the degradation technology screening module comprises:

[0018] Diffusion model construction unit: used for constructing an aeration zone pollutant diffusion model based on Fick's law;

[0019] Reaction rate calculation unit: used for calculating the reaction rate constant of different degradation technologies by Monod kinetics equation;

[0020] Product safety verification unit: used for verifying the safety of the degradation products based on isotope tracing method.

[0021] Further, the removal technology screening module comprises:

[0022] Solute transport simulation unit: constructs an aquifer solute transport model based on Darcy's law;

[0023] Removal efficiency calculation unit: calculates the pollutant removal amount per unit time of different removal technologies by equivalent substitution method;

[0024] Economic comparison unit: compares the economy of different technologies based on a whole life cycle cost model.

[0025] Further, the degradation technology screening module further comprises:

[0026] residual load transfer unit: for outputting residual pollutant load screened by the degradation technology screening module as input condition of the removal technology screening module;

[0027] risk constraint unit: environmental risk parameter evaluated by the degradation technology screening module as constraint condition of the removal technology screening module.

[0028] Further, the whole-cycle cost benefit verification of the cost accounting module includes:

[0029] cost modeling unit: establishing a whole-cycle cost model including material cost, equipment cost and operation cost;

[0030] economic benefit calculation unit: calculating comprehensive economic benefit based on agricultural production income and environmental governance derived benefit;

[0031] investment feasibility evaluation unit: evaluating investment feasibility of the technical scheme by net present value method.

[0032] Further, it further includes:

[0033] data storage module: for storing technical parameters, evaluation results and cost data in the screening process of each module;

[0034] decision support module: for providing technical combination optimization suggestion based on data of the data storage module.

[0035] Further, the data storage module includes:

[0036] technical parameter database: configured to store technical parameters and model parameters used by each screening module;

[0037] evaluation result database: configured to store evaluation results and screening conclusions of each screening module;

[0038] cost database: configured to store whole-cycle cost data and economic benefit data.

[0039] Further, the decision support module includes:

[0040] technical combination optimization unit: configured to generate multiple technical combination schemes based on data of the data storage module;

[0041] sensitivity analysis unit: configured to perform sensitivity analysis on different technical combination schemes to evaluate influence of parameter change on results;

[0042] scheme recommendation unit: configured to recommend optimal scheme from multiple technical combination schemes according to preset decision standard.

[0043] In a second aspect, a method for screening agricultural non-point source groundwater pollution remediation technology includes:

[0044] S1, determining the optimal barrier technology of the farmland infiltration link through a barrier technology screening module;

[0045] S2, determining the adaptive degradation technology of the air gap link based on the optimal barrier technology through a degradation technology screening module;

[0046] S3, determining the economically viable removal technology of the aquifer link based on the adaptive degradation technology through a removal technology screening module;

[0047] S4, performing full-cycle cost-benefit verification on the optimal barrier technology, adaptive degradation technology and economically viable removal technology through a cost accounting module to generate a final technical solution.

[0048] Compared with the prior art, the above-mentioned agricultural non-point source groundwater pollution remediation technology screening system and method provided by the present application quantitatively evaluates the pollutant barrier ability of the barrier technology to the farmland infiltration through the soil hydraulics equation, screens the air gap high-efficiency degradation technology by using the Fick's law and the Monod kinetics model, and verifies the economic feasibility of the aquifer removal technology based on the shadow engineering method and the full life cycle cost model. The farming compatibility standard and the environmental safety threshold are introduced to ensure the coordination of the technology and the farmland ecology. The method specifically comprises: determining the optimal technology of the farmland infiltration, air gap and aquifer link through the modules in sequence, and generating a feasible solution by combining the cost accounting, solving the problems of poor adaptability and high cost of the traditional technology in the agricultural scene, and realizing the precise screening and economically viable remediation technology combination of the whole chain from the pollution source to the end. BRIEF DESCRIPTION OF DRAWINGS

[0049] Figure 1 The architecture diagram of the agricultural non-point source groundwater pollution remediation technology screening system provided by the embodiment of the present application is shown. DETAILED DESCRIPTION

[0050] The technical solutions of the present application will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are not all the embodiments of the present application, and all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0051] It should be noted that, unless otherwise specified, the relative arrangement and numerical expression of the components and steps described in these embodiments should not be understood as limiting the scope of the present application.

[0052] The following description of example embodiments is merely illustrative in nature and is in no way intended to limit the application or its application or uses. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art can not be discussed in detail herein, but should be considered part of the specification if applicable.

[0053] Embodiment one

[0054] Referring to Figure 1 The present application provides an agricultural non-point source groundwater pollution remediation technology screening system. The system adopts a progressive architecture. According to the migration path of agricultural non-point source pollution, i.e. farmland infiltration, vadose zone migration and aquifer accumulation, the system sequentially sets a barrier technology screening module, a degradation technology screening module and a removal technology screening module, and verifies the cost-effectiveness of the whole cycle through a cost accounting module. The modules are closely related through data transmission and constraint conditions. Specifically, it can include:

[0055] A1, the barrier technology screening module: for evaluating the barrier ability of the technology to the infiltration of pollutants from farmland through quantitative calculation, and screening the technology compatible with farmland cultivation; the module is composed of a permeability coefficient calculation unit, a nitrogen fertilizer loss evaluation unit and a compatibility verification unit; specifically, it can include:

[0056] A11, the permeability coefficient calculation unit: for calculating the influence of different materials on the permeability coefficient of pollutants based on the soil hydraulics equation;

[0057] Richards equation is used as the basic equation of soil hydraulics, and USDA soil texture classification parameters are introduced to calculate the influence of different barrier materials on the permeability coefficient of pollutants. Specifically, it includes bentonite, biochar and high molecular polymer; the equation expression is:

[0058]

[0059] wherein, is the soil volumetric water content, is the time, is the unsaturated hydraulic conductivity, is the pressure head, is the gravity head. The equation is solved by numerical simulation software HYDRUS-1D to obtain the permeability coefficient of different materials under different compaction and water content conditions.

[0060] A12, the nitrogen fertilizer loss evaluation unit: for calculating the nitrogen fertilizer loss reduction rate through a parameterized evaluation model; a parameterized evaluation model is constructed, based on the law of conservation of mass and the convection-dispersion equation, to calculate the nitrogen fertilizer loss reduction rate of different barrier technologies. The specific model expression is:

[0061]

[0062] wherein, is the nitrogen loss concentration under non-barrier conditions, is the nitrogen loss concentration under barrier conditions. Model parameters include soil texture, rainfall intensity, fertilizer amount, barrier thickness, etc., which are determined through field experiments or literature data.

[0063] A13, compatibility verification unit: for evaluating the compatibility of the soil physical property change model with farmland tillage. A soil physical property change model is established to evaluate the impact of the barrier technology on soil bulk density, porosity, and field moisture capacity. The model is based on the theory of soil three-phase composition, and the expression is:

[0064]

[0065] wherein, is the soil bulk density, is the soil particle density, is the porosity. By comparing the changes in soil physical properties before and after adding barrier materials, the compatibility of the technology with farmland tillage is determined. If the change in soil bulk density is not more than 10% and the change in porosity is not more than 5%, the technology is considered compatible with farmland tillage.

[0066] The barrier technology screening module is the first line of defense for pollution prevention and control, mainly targeting the infiltration link of farmland. It screens technologies that can form an effective barrier layer in the plow sole layer. The screening results directly affect the pollutant load entering the aeration zone, providing initial conditions for the degradation technology screening module.

[0067] A2, degradation technology screening module: for screening based on the results of the barrier technology screening module, targeting pollutant components with strong migration ability, and evaluating the degradation ability of the technology for pollutants in the aeration zone through experimental simulation or empirical data, screening technologies with high degradation efficiency and low environmental risk; specifically, it can include:

[0068] A21, diffusion model construction unit: for constructing an aeration zone pollutant diffusion model based on Fick's law to describe the diffusion process of pollutants in soil pores; the specific expression is:

[0069]

[0070] wherein, is the pollutant concentration, is the time, is the diffusion coefficient in soil. Considering the impact of changes in water content in the aeration zone on the diffusion process, the diffusion coefficient Ds is calculated using the Millington-Quirk model, and the specific expression is:

[0071]

[0072] wherein, D is the diffusion coefficient of the contaminant in free water, θ is the volumetric water content of the soil, θs is the saturated water content.

[0073] A22, a reaction rate calculation unit: for calculating the reaction rate constant of different degradation technologies by Monod kinetics equation; the specific expression is:

[0074]

[0075] wherein, r is the reaction rate, μmax is the maximum specific growth rate, S is the substrate concentration, Ks is the half-saturation constant, X is the microbial concentration. Through indoor soil column experiments or literature data, the kinetic parameters of different degradation technologies (such as denitrifying bacteria, nano zero-valent iron) are fitted to obtain and .

[0076] A23, a product safety verification unit: for verifying the safety of degradation products based on isotope tracing method. Adopting isotope tracing method (such as 15N labeling) to trace the conversion path and product distribution of contaminants in the degradation process;

[0077] and analyzing the types and concentrations of degradation products by mass spectrometer (such as GC-MS, LC-MS) to evaluate the environmental safety of products; setting the product safety threshold, such as the ammonia nitrogen concentration not exceeding 5 mg / L, the nitrite concentration not exceeding 1 mg / L, to ensure that the degradation process will not produce secondary pollution.

[0078] A24, a residual load transfer unit: for transferring the residual contaminant load output by the degradation technology screening module as the input condition of the removal technology screening module; according to the diffusion model and the reaction rate calculation result, determining the contaminant load remaining after degradation treatment. The residual load calculation formula is:

[0079]

[0080] wherein, the initial load is the contaminant 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 transferred to the solute transport simulation unit as the input condition of the removal technology screening module.

[0081] A25, risk constraint unit: the environmental risk parameters evaluated by the degradation technology screening module are used as the constraint conditions of the removal technology screening module. Based on the results of the product safety verification unit, the environmental risk parameters in the degradation process are extracted, including, for example, ammonia nitrogen concentration and nitrite concentration. These risk parameters are used as the constraint conditions of the removal technology screening module to ensure that the subsequent removal technology can effectively handle these potential secondary pollutants.

[0082] The degradation technology screening module focuses on pollutants with strong migration ability in the vadose zone based on the results of the barrier module, and screens high-efficiency and low-risk degradation technologies. The residual pollutant load and environmental risk parameters output by the degradation technology screening module are used as input conditions and constraint conditions of the removal technology screening module.

[0083] A3, removal technology screening module: based on the results of the degradation technology screening module, the shadow engineering algorithm is used to compare the removal efficiency of pollutants in the aquifer by different technologies, and the removal efficiency and cost of different technologies for removing pollutants in the aquifer are quantified by constructing a virtual remediation project. Specifically, it can include:

[0084] A31, solute transport simulation unit: based on Darcy's law, an aquifer solute transport model is constructed;

[0085] Based on Darcy's law and the convection-dispersion equation, an aquifer solute transport model is constructed to describe the migration process of pollutants in the aquifer. The specific expression is:

[0086]

[0087] wherein, is the retardation factor, is the pollutant concentration, is the time, is the hydrodynamic dispersion coefficient, is the actual flow rate of groundwater, and λ is the first-order reaction rate constant. The equation is solved by numerical simulation software (such as MODFLOW, MT3DMS) to obtain the pollutant concentration distribution and removal effect under the action of different removal technologies (such as pumping-treatment-reinjection, in-situ chemical oxidation).

[0088] A32, removal efficiency calculation unit: the equivalent replacement method is used to calculate the pollutant removal amount per unit time of different removal technologies. For the pumping-treatment-reinjection technology, the removal amount calculation formula is:

[0089]

[0090] wherein, is the removal amount per unit time, is the pumping amount, Ci is the concentration of pollutants in the influent water, Ci is the concentration of pollutants in the effluent water. For in-situ remediation technology, the equivalent removal amount per unit time is calculated by comparing the change of pollutant concentration before and after remediation, combined with the volume of the remediation area and the remediation time.

[0091] A33, economic comparison unit: compare the economy of different technologies based on the life cycle cost model. Calculate the total cost of different removal technologies, including material cost, equipment cost, operation cost, maintenance cost and monitoring cost. The specific expression is:

[0092]

[0093] Wherein, Total cost, Cost in the ith year, Discount rate. Compare the unit removal cost (yuan / kg of pollutants) of different technologies, and select the removal technology with the best economy.

[0094] The removal technology screening module is the end treatment link. According to the results of the degradation technology screening module, the economically feasible removal technology suitable for aquifer is screened. Through the progressive correlation of the barrier technology screening module, the degradation technology screening module and the removal technology screening module, a complete technology screening chain is formed.

[0095] A4, cost accounting module: based on the results of the degradation technology screening module, the full cycle cost benefit verification is carried out and the feasible technology scheme is generated. Specifically, it can include:

[0096] A41, cost modeling unit: establish a full cycle cost model including material cost, equipment cost and operation cost;

[0097] Material cost is calculated according to the type, amount and market price of the required materials; equipment cost includes equipment purchase, installation and commissioning cost; operation cost includes energy consumption, reagent consumption, labor cost, etc.; maintenance cost includes equipment maintenance, replacement parts, etc.; monitoring cost includes regular sampling, analysis and testing, etc. The model takes into account the time factor, and uses the discount rate to convert future cost into present value.

[0098] A42, economic benefit calculation unit: calculate the comprehensive economic benefit based on agricultural production income and environmental governance derived benefit; production income includes fertilizer saving, water saving and yield increase benefit; the calculation formula of fertilizer saving benefit is:

[0099]

[0100] Wherein, Fertilizer saving benefit, Reduced fertilizer amount, For fertilizer prices. Water-saving benefits. and increased production benefits Using a similar method, the overall economic benefit is the sum of the benefits of each individual benefit.

[0101] In addition, the benefits derived from environmental governance include carbon sequestration revenue ( ) and benefits of water quality improvement ( Carbon sequestration revenue is based on the quantification of ecological carbon sequestration value using soil carbon sequestration capacity, and the calculation formula is as follows:

[0102]

[0103] in, This refers to the amount of carbon sequestration per unit area of ​​soil. This refers to the unit price for carbon trading.

[0104] The benefits of improved water quality are quantified by the reduction in water treatment costs and ecological value after groundwater pollution remediation. The calculation formula is as follows:

[0105]

[0106] in, The regional groundwater extraction volume is determined based on hydrogeological data. and These represent the pollutant concentrations before and after treatment; Cost per unit of pollutant treatment; The cost of purchasing water saved through reclaimed water reinjection.

[0107] The comprehensive economic benefits are derived by calculating the income from agricultural production and the derivative benefits from environmental governance. The specific calculation formula is as follows:

[0108]

[0109] Agricultural production income and environmental governance-related benefits are calculated separately to form a full-cycle benefit matrix.

[0110] A43. Investment Feasibility Assessment Unit: This unit assesses the investment feasibility of the technical solution using the Net Present Value (NPV) method. The NPV calculation formula is:

[0111]

[0112] in, For the revenue in year t, For the first Annual cost, The discount rate is used. If NPV > 0, the technical solution is considered economically feasible; if NPV < 0, the technical parameters need to be adjusted or other technical combinations need to be selected, and the cost-benefit analysis needs to be performed again.

[0113] A5, Data storage module: composed of technical parameter database, evaluation result database and cost database; specifically can include:

[0114] A51, Technical parameter database: stores technical parameters and model parameters used by each screening module, including soil physical property parameters, pollutant characteristic parameters and technical performance parameters, etc.

[0115] Among them, the soil physical property parameters include bulk density, porosity, permeability, soil texture and field moisture capacity, etc.; the pollutant characteristic parameters include diffusion coefficient and reaction rate constant; the technical performance parameters include barrier layer thickness, degradation efficiency and removal rate.

[0116] A relational database (such as MySQL) is used for management, and parameter tables, material tables, model tables and other data tables are established, different data tables are associated through unique identifiers (such as UUID), and parameter cross-module calling and tracing are realized. Among them, the parameter table can record various physical or chemical parameters, the material table stores the properties of bentonite or humic acid, and the model table saves formula parameters and version information.

[0117] A52, Evaluation result database: stores the evaluation results and screening conclusions of each screening module; the barrier technology screening results include the permeability coefficient of the barrier technology screening module and the nitrogen loss reduction rate; the degradation technology screening results include the degradation efficiency and the product safety evaluation results; the removal technology screening results include the pollutant removal amount per unit time, the economic comparison results and the technical feasibility conclusion.

[0118] The management mode uses a time series database (such as InfluxDB) to store dynamic data, supports indexing by timestamp; built-in trend analysis engine, automatically generates curves of evaluation results changing with time (such as quarterly / annual barrier efficiency fluctuation chart); at the same time, supports docking with GIS system, realizes visualization of spatialized evaluation results.

[0119] A53, Cost database: stores whole-cycle cost data, economic benefit data and comparative analysis data; among them, the whole-cycle cost data includes material cost, equipment cost, operation cost, maintenance cost and monitoring cost; the economic benefit data includes fertilizer saving income, water saving income, yield increase income and carbon sink income; the comparative analysis data includes total cost comparison, cost composition proportion and investment recovery period calculation results of different technology combinations.

[0120] The management mode uses data warehouse technology (such as Hive) to realize hierarchical storage of massive data, supports multi-dimensional analysis (such as by region / technology type / time dimension), generates cost-benefit report (such as annual cost trend table, technology combination ROI comparison chart); integrates data visualization tools (such as Tableau), dynamically displays cost structure tree chart, income trend curve, etc.

[0121] A6, Decision support module: composed of technology combination optimization unit, sensitivity analysis unit and scheme recommendation unit; specifically can include:

[0122] 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 schemes.

[0123] The optimization objectives include maximizing pollutant removal efficiency, minimizing cost, and minimizing environmental risk, and the constraint conditions include technology compatibility, processing capacity, investment budget, etc.

[0124] Through algorithm iteration calculation, a Pareto optimal solution set is obtained, and each solution represents a feasible technology combination scheme.

[0125] A62, Sensitivity analysis unit: sensitivity analysis is performed 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.

[0126] Using the Monte Carlo simulation method, the probability distribution of the parameters is generated by random sampling, and the sensitivity coefficients of each parameter on the objective function are calculated.

[0127] Based on the results of sensitivity analysis, the key factors affecting the performance of the technology scheme are identified, which provides a basis for scheme optimization.

[0128] A63, Scheme recommendation unit: according to the preset decision criteria, including economic benefit priority, environmental benefit priority and comprehensive benefit optimization, the optimal scheme is recommended from multiple technology combination schemes.

[0129] For the decision criteria of economic benefit priority, the scheme with the maximum NPV is selected; for the decision criteria of environmental benefit priority, the scheme with the highest pollutant removal efficiency and the lowest environmental risk is selected; for the decision criteria of comprehensive benefit optimization, the analytic hierarchy process (AHP) is used to consider multiple indexes, the comprehensive scores of each scheme are calculated, and the scheme with the highest score is selected.

[0130] Example two

[0131] Referring to Figure 1 , the present application provides a kind of agricultural non-point source groundwater pollution remediation technology screening method, specific steps include:

[0132] S1, determine the optimal barrier technology of farmland infiltration link through barrier technology screening module; collect the barrier material / technology suitable for farmland, including: bentonite, kaolin, humic acid, barrier membrane and lime powder;The influence of material on the permeability coefficient of pollutants is calculated by Richards equation, combined with the data of North China Plain field, the nitrogen fertilizer loss reduction rate is quantified;Referring to Table 1:

[0133] Table 1 calculation results

[0134]

[0135] When 2000 kg of bentonite or kaolin is uniformly applied per mu, after 3-5 years of cultivation, both can be deposited in the plow layer to form a barrier layer, achieving the effect of reducing nitrogen loss by 40% (about 10 kg of nitrogen per year), increasing crop nitrogen absorption by 5 kg per year, and saving irrigation water by 50 mu per year, and no obvious side effects; while applying 500 kg of humic acid, 100 kg of which is lost, 300 kg is mixed with soil particles, and 100 kg is deposited in the plow layer, which can only reduce nitrogen loss by 20% (about 5 kg of nitrogen per year), increase crop nitrogen absorption by 2 kg per year, and there is a risk of crop diseases caused by high application.

[0136] In summary, bentonite and kaolin are significantly superior to other technologies in barrier ability, environmental adaptability, operational feasibility and economy, and are the best choice.

[0137] S2, based on the optimal barrier technology, determine the adaptive degradation technology for the vadose zone link through the degradation technology screening module; nitrate has the strongest migration ability in agricultural non-point source pollution, and is selected as the target pollutant for degradation technology screening.

[0138] In the degradation technology screening, for nitrate with the strongest migration ability in agricultural non-point source pollution, the cost of denitrifying bacteria liquid is 100 yuan / ton, and 10 tons are added per mu (including 10 yuan / ton of addition fee), with an active period of 3 months, and 2 times per year (wheat and corn growing season) can reduce 99% of the infiltrated nitrate to nitrogen or ammonia nitrogen, with an annual cost of 2200 yuan per mu, and no interference from cultivation; nano iron is expensive (cost is more than 10 times that of bacteria liquid), and it is difficult to accurately reduce nitrate to nitrogen, and it is easy to generate ammonia nitrogen causing secondary pollution, with significant technical disadvantages. After screening, denitrifying bacteria liquid becomes the only feasible technology due to its low cost, high efficiency and no impact on agricultural production.

[0139] S3, based on the adaptive degradation technology, determine the economically feasible removal technology for the aquifer link through the removal technology screening module; select the aquifer remediation technology with high removal efficiency per unit time and controllable cost.

[0140] The shadow engineering method is used to evaluate four aquifer remediation technologies under the condition of 667m2 farmland, 10m thick aquifer and 100mg / L nitrate concentration: the extraction treatment technology can reduce the nitrate concentration by more than 50% in 2 days by setting 4 500m3 / day water wells, and the cost of pumping is only 50 yuan / acre (the cost of new well network is 10000 yuan / acre, which can be used continuously), and the extracted liquid can be used for irrigation; the in-situ reduction / denitrification technology has the problems of high cost of reagent, insufficient efficiency of less than 40% (only partial conversion of nitrate and fast consumption of bacterial agent); the construction cost of in-situ barrier technology is more than 20000 yuan / acre, and the technology is not economically feasible. Through the comparison of efficiency and cost, the extraction treatment technology has a significantly higher removal rate per unit time, and if the existing well network is reused, the capital cost can be greatly reduced, so it is selected as the optimal solution, especially suitable for areas covered by existing well networks.

[0141] S4, verifying the optimal barrier technology, the adaptive degradation technology and the economically feasible removal technology by the cost accounting module, and generating a final technical solution.

[0142] In summary, the present application has the following advantages:

[0143] (1) The adaptability of the technology in each link is quantitatively evaluated by the soil hydraulics equation, which solves the defect of ignoring the migration mechanism of agricultural pollution in traditional methods;

[0144] (2) A single-link cost quantification model and a comprehensive cost decision mechanism are established to eliminate technologies that exceed the budget and to select a technology combination that saves costs compared to traditional solutions;

[0145] (3) The threshold of tillage compatibility and the environmental safety index are set to ensure the coordination of the technology and the farmland ecology.

[0146] The above specific embodiments are only used to illustrate the technical solutions of the present application and not to limit it, although the present application has been described in detail with reference to examples, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the present application, and they should be covered in the scope of the claims of the present application.

Claims

1. An agricultural non-point source groundwater pollution remediation technology screening system, characterized in that, The application relates to a pollution control system for farmland, which comprises a barrier technology screening module, a degradation technology screening module, a removal technology screening module, a cost accounting module, a data storage module and a decision support module. The barrier technology screening module comprises a permeability coefficient calculation unit, a nitrogen fertilizer loss evaluation unit and a compatibility verification unit. The degradation technology screening module comprises a diffusion model construction unit, a reaction rate calculation unit and a product safety verification unit. The removal technology screening module comprises a solute transport simulation unit, a removal efficiency calculation unit and an economic comparison unit. The cost accounting module comprises a cost modeling unit, an economic benefit calculation unit and an investment feasibility evaluation unit. The data storage module comprises a technical parameter database, an evaluation result database and a cost database. The decision support module provides technical combination optimization suggestions based on the data in the data storage module. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2. The agricultural non-point source groundwater pollution remediation technology screening system according to claim 1, characterized in that, ​ ​ ​ 3. The agricultural non-point source groundwater pollution remediation technology screening system according to claim 2, characterized in that, ​ ​ ​ ​ 4. The agricultural non-point source groundwater pollution remediation technology screening system according to claim 2, characterized in that, The decision support module comprises: a technical combination optimization unit configured to generate multiple technical combination schemes based on the data of the data storage module; a sensitivity analysis unit configured to perform sensitivity analysis on different technical combination schemes to evaluate the influence of parameter changes on results; a scheme recommendation unit configured to recommend an optimal scheme from the multiple technical combination schemes according to a preset decision standard.

5. The method for screening agricultural non-point source groundwater pollution remediation technology according to any one of claims 1-4, applied to the screening system for agricultural non-point source groundwater pollution remediation technology. comprise: S1, determining the optimal barrier technology of the farmland infiltration link through the barrier technology screening module; S2, based on the optimal barrier technology, determining the adaptive degradation technology of the air zone link through the degradation technology screening module; S3, based on the adaptive degradation technology, determining the economically feasible removal technology of the aquifer link through the removal technology screening module; S4, performing full-cycle cost-benefit verification on the optimal barrier technology, adaptive degradation technology and economically feasible removal technology through the cost accounting module to generate a final technical scheme.

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