A Method for Identifying the Type and Determining the Volume of Solid Waste Landfill Based on Induced Polarization Signals

Abstract

The present invention relates to the technical field of soil and groundwater pollution investigation, and specifically relates to a method for identifying the type and determining the volume of solid waste landfills based on induced polarization signals. Step 1: Collect induced polarization data in the research area; Step 2: Select abnormal points of electrical characteristics according to the inversion results; Step 3: Collect soil and groundwater samples at the abnormal points and analyze the content of characteristic pollutants; Step 4: Establish the correlation between induced polarization parameters and the content of characteristic pollutants; Step 5: Define the induced polarization signal threshold for identifying landfills; Step 6: Determine the distribution and volume of the main types of landfills. The method of the present invention is simple to operate and has wide applicability. It can accurately depict the heterogeneity of underground porous media, accurately identify the types of solid waste landfills, locate their ranges and calculate their volumes, providing a basis and comprehensive technical guarantee for risk control, pollution remediation plan formulation and ecological environment prevention and control, and effectively saving economic costs.

Description

Technical Field

[0001] The present invention relates to the technical field of soil and groundwater pollution investigation, and in particular to a method for identifying the type and volume of solid waste landfill based on induced polarization signals. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] The old solid waste landfills left over from history lack standardized gas or leachate recovery systems, which is a major environmental crisis facing soil and groundwater. The identification of solid waste landfills and the surrounding uncontaminated soil environment and the accurate characterization of their scope have a huge impact on the advancement of soil and groundwater pollution investigation and remediation work, and are the basis for assessing the environmental status of soil and groundwater. Identifying the type and volume of solid waste landfills in contaminated sites can provide a basis for the formulation of risk control and pollution remediation plans, effectively save economic costs, and ensure the rational use of land resources.

[0004] At present, the main means of environmental pollution investigation of solid waste landfills include invasive drilling, non-invasive geophysical exploration and other methods. Pollution distribution characterization technology based on invasive drilling sampling and experimental analysis has disadvantages such as high cost, poor spatial coverage, and discontinuous information. Non-invasive geophysical exploration technology is suitable for various complex terrains, has a wide coverage range, and has low application cost. It can realize remote, non-destructive dynamic investigation and monitoring of soil-groundwater pollution. However, geophysical exploration obtains physical signals such as resistivity and polarizability of underground porous media, and cannot directly obtain pollution concentration information, which easily increases human uncertainty when interpreting data. Summary of the invention

[0005] In order to solve the technical problems existing in the above-mentioned background technology, the present invention provides a method for identifying the type and determining the volume of solid waste landfill based on induced polarization signals. The method is simple to operate and has wide applicability. It can accurately characterize the heterogeneity of underground porous media, accurately identify the type of solid waste landfill, locate its range and calculate its volume, provide a basis and comprehensive technical guarantee for the formulation of risk management and pollution remediation plans and ecological environmental prevention and control, and effectively save economic costs.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A first aspect of the present invention provides a method for identifying the type and volume of solid waste landfill based on induced polarization signals.

[0008] A method for identifying the type and volume of solid waste landfill based on induced polarization signals, comprising:

[0009] Layout background survey lines, obtain laser polarization signals at the background survey lines, collect induced polarization data, perform preprocessing, and then perform inversion;

[0010] According to the inversion results, select abnormal points of electrical characteristics;

[0011] Collect soil and groundwater samples at the abnormal points of electrical characteristics and analyze the content of characteristic pollutants;

[0012] Extract the induced polarization parameters of the soil and groundwater sample collection points in the inversion profile, select the induced polarization parameters with a correlation coefficient greater than the set threshold with the content of characteristic pollutants, and establish the correlation between the induced polarization parameters and the content of characteristic pollutants;

[0013] Based on the correlation between the induced polarization parameters and the content of characteristic pollutants, adjust and determine one or more induced polarization signal thresholds for identifying landfill materials;

[0014] According to the induced polarization parameters, identify the types of solid waste landfills. Based on the induced polarization signal threshold, select the distribution range of the designated solid waste landfills and calculate the volume of each type of solid waste landfill.

[0015] Further, the induced polarization parameters include: complex resistivity amplitude, complex conductivity amplitude, real part conductivity, imaginary part conductivity, polarization rate, and phase difference.

[0016] Further, select the real part conductivity, imaginary part conductivity, and the content of characteristic pollutants as the indicators for identifying the types of landfills and determining the volume of landfills;

[0017] (1) σ′ < 40 mS / m, σ″ < 1 mS / m, TOC < 1000 mg / kg, construction waste;

[0018] (2) 40 mS / m < σ′ < 80 mS / m, 1 mS / m < σ″ < 3 mS / m, 1000 mg / kg < TOC < 1500 mg / kg, domestic waste with low water content;

[0019] (3) 80 mS / m < σ′ < 200 mS / m, 3 mS / m < σ″ < 10 mS / m, 1500 mg / kg < TOC < 2000 mg / kg, domestic waste with high water content;

[0020] (4) σ′ > 200 mS / m, σ″ > 10 mS / m, TOC > 2000 mg / kg, area with active microorganisms;

[0021] Among them, σ′ represents the selected real part conductivity, σ″ represents the imaginary part conductivity, and TOC represents the content of characteristic pollutants.

[0022] Further, the abnormal points of electrical characteristics include high resistivity and high polarizability regions, high resistivity and low polarizability regions, low resistivity and high polarizability regions, and low resistivity and low polarizability regions.

[0023] Further, after selecting the abnormal points of electrical characteristics, it also includes: controlling the number of boreholes, each borehole passing through multiple abnormal points of electrical characteristics, and at the same time selecting a background point on the background survey line as a control for the polluted point.

[0024] Further, when collecting soil and groundwater samples at the abnormal points of electrical characteristics, if groundwater is exposed by the borehole, measure the salinity for use as a control for the inversion results.

[0025] Further, based on the induced polarization signal threshold, select the distribution range of the designated solid waste landfill. The method includes: comprehensively analyzing the inversion profile results of all background survey lines to obtain the three-dimensional distribution of the induced polarization parameters in the entire study area, and cutting the distribution range of the landfill according to the selected induced polarization signal threshold.

[0026] Further, the preprocessing process includes: removing and interpolating and replacing large false or mutated abnormal data.

[0027] Further, arranging background survey lines includes densifying the background survey lines by 2-3 times in the potential key pollution areas.

[0028] The second aspect of the present invention provides a system for identifying the type and determining the volume of solid waste landfills based on induced polarization signals.

[0029] A system for identifying the type and determining the volume of solid waste landfills based on induced polarization signals, characterized by including:

[0030] An induced polarization and inversion module, which is configured to: arrange background survey lines, laser polarization signals at the background survey lines, collect induced polarization data, perform preprocessing, and then perform inversion;

[0031] An abnormal point selection module, which is configured to: select abnormal points of electrical characteristics according to the inversion results;

[0032] A collection and testing module, which is configured to: collect soil and groundwater samples at the abnormal points of electrical characteristics and test the content of characteristic pollutants;

[0033] A correlation relationship establishment module, which is configured to: extract the induced polarization parameters of the soil and groundwater sample collection points from the inversion profile, select the induced polarization parameters with a correlation coefficient greater than the set threshold with the content of characteristic pollutants, and establish a correlation relationship between the induced polarization parameters and the content of characteristic pollutants;

[0034] A threshold determination module, configured to: based on the correlation between induced polarization parameters and the content of characteristic pollutants, adjust and determine one or more induced polarization signal thresholds for identifying landfilled materials;

[0035] A type identification and volume determination module, configured to: identify the type of solid waste landfill based on the induced polarization parameters, select the distribution range of the designated solid waste landfill based on the induced polarization signal threshold, and calculate the volume of each type of solid waste landfill.

[0036] Compared with the prior art, the beneficial effects of the present invention are:

[0037] The present invention provides a method for identifying the type and determining the volume of solid waste landfills based on induced polarization signals. By inversely analyzing the induced polarization data collected in the study area and specifically testing the soil and groundwater samples at the points with abnormal electrical properties, the correlation between induced polarization parameters and the content of characteristic pollutants is established, providing technical support for the accurate characterization of solid waste landfills. This method is simple to operate, widely applicable, can accurately characterize the heterogeneity of underground porous media, accurately identify the type of solid waste landfill, locate its range and calculate its volume, providing a basis and comprehensive technical guarantee for risk control, pollution remediation plan formulation, and ecological environment prevention and control, and effectively saving economic costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0039] Figure 1 is a flowchart of the method for identifying the type and determining the volume of solid waste landfills based on induced polarization signals shown in the present invention;

[0040] Figure 2 is a schematic diagram of the corresponding relationship between real part conductivity and TOC test results shown in the present invention;

[0041] Figure 3 is a schematic diagram of the corresponding relationship between imaginary part conductivity and TOC test results shown in the present invention;

[0042] Figure 4 is a schematic diagram of the corresponding relationship between phase difference parameters and TOC test results shown in the present invention;

[0043] Figure 5 is a schematic diagram of the relationship among real part conductivity, imaginary part conductivity, and TOC content shown in the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0044] The present invention will be further described below in conjunction with the drawings and embodiments.

[0045] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0046] It should be noted that the terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly dictates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0047] It should be noted that the flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of methods and systems according to various embodiments of the present disclosure. It should be noted that each block in the flowchart or block diagram may represent a module, a program segment, or a part of code, and the module, program segment, or part of code may include one or more executable instructions for implementing the logical functions specified in each embodiment. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than marked in the accompanying drawings. For example, two consecutive blocks shown may actually be executed substantially in parallel, or they may sometimes be executed in the reverse order, depending on the functions involved. Similarly, it should be noted that each block in the flowchart and / or block diagram, and combinations of blocks in the flowchart and / or block diagram, can be implemented using a dedicated hardware-based system that performs the specified functions or operations, or can be implemented using a combination of dedicated hardware and computer instructions.

[0048] Embodiment 1

[0049] As Figure 1 shown, this embodiment provides a method for identifying the type and determining the volume of solid waste landfills based on induced polarization signals, including the following steps:

[0050] Collect induced polarization data in the study area;

[0051] Select abnormal points of electrical characteristics according to the inversion results;

[0052] Collect soil and groundwater samples at the abnormal points and analyze the content of characteristic pollutants;

[0053] Establish the correlation between induced polarization parameters and the content of characteristic pollutants;

[0054] Define the threshold of induced polarization signals for identifying landfills;

[0055] Determine the distribution and volume of the main types of landfills.

[0056] As Figure 1 shown, the method for identifying the type and determining the volume of solid waste landfills based on induced polarization signals of the present invention includes the following steps:

[0057] Step 1: Collect induced polarization data in the study area, and at the same time arrange background survey lines, and encrypt the survey lines in potential key pollution areas. The specific process is as follows: According to the preliminary survey data of the study area in the early stage, select a survey line position as the background survey line and collect induced polarization data. According to the on-site induced polarization signal collection process, adjust the survey line layout plan at any time, and encrypt the survey lines in potential key pollution areas by 2-3 times. Adopt the data collection method of separating the supply and measurement cables to reduce the electrode polarization phenomenon and electromagnetic coupling effect. At the same time, use stainless steel electrodes as the power supply electrodes and non-polarizable electrodes as the measurement electrodes to ensure the quality of the data signal.

[0058] Step 2: Check whether there are abnormal data points in the measurement data, and perform data processing and inversion, and select the abnormal points of electrical property characteristics according to the inversion results. The specific process is as follows: Before inversion, it is necessary to eliminate and interpolate and replace the large false or mutated abnormal data caused by external interference or poor electrode grounding, etc., to eliminate or reduce its adverse impact on the inversion results. Comparing the inversion results of the background survey line profile, focus on delineating the areas with high resistivity and high polarization rate, high resistivity and low polarization rate, low resistivity and high polarization rate, and low resistivity and low polarization rate that are aggregated and distributed as the abnormal points of electrical property characteristics. Control the number of boreholes, and each borehole should pass through as many abnormal points of electrical property characteristics as possible. At the same time, select a background point on the background survey line as a control for the pollution points.

[0059] Step 3: Collect soil and groundwater samples at the abnormal points and test the content of characteristic pollutants. The specific process is as follows: When collecting samples at the abnormal points, if groundwater is exposed in the borehole, it is necessary to measure the salinity on site for comparison with the inversion results. The selected characteristic pollutants need to refer to the preliminary survey data of the study area in the early stage to determine the types of inorganic salts, heavy metals, organic matters, etc. to be tested. Standardize the whole process of soil and groundwater sample collection, preservation, transfer, and testing to ensure the authenticity and referenceability of the test data.

[0060] Step 4: Extract the induced polarization parameters of the soil and groundwater sample collection points in the inversion profile, and establish the correlation between the induced polarization parameters and the content of characteristic pollutants. The specific process is as follows: The selection of induced polarization parameters depends on the selection of the data inversion model, including complex resistivity amplitude, complex conductivity amplitude, real part conductivity, imaginary part conductivity, polarization rate, and phase difference. Extract the induced polarization parameters of the soil and groundwater sample collection points in the inversion profile. Calculate the correlation coefficient between the induced polarization parameters and the content of characteristic pollutants, and select 1-2 induced polarization parameters with strong correlation to establish the correlation between the two.

[0061] The correlation coefficient calculation formula is:

[0062]

[0063] Where: Cov(X,Y) is the covariance of the induced polarization parameter X and the characteristic pollutant content Y, Var[X] is the variance of the induced polarization parameter X, and Var[Y] is the variance of the characteristic pollutant content Y.

[0064] The relevant relationship expression is:

[0065] Y=a ln X+b

[0066] or,

[0067] Y=ae bX

[0068] Where: a and b are fitting empirical coefficients.

[0069] Step 5: Compare the induced polarization inversion profile results with the test results of groundwater and soil samples to define the induced polarization signal threshold for identifying landfills. The specific process is: Comprehensively analyze the inversion results of all survey lines and preliminarily define the signal threshold for potential landfills. Compare the characteristic pollutant content of all points to screen out the induced polarization parameter range corresponding to the background value concentration and risk value concentration. Comprehensively analyze the inversion results of the survey lines and the test results of soil and groundwater samples to adjust and determine one or more induced polarization signal thresholds for identifying landfills.

[0070] Step 6: Determine the distribution and volume of the main types of landfills. The specific process is: when identifying the main types of solid waste landfills based on the induced polarization signal, construction waste mixed with a large amount of metallic iron, low-concentration NAPLs pollutants, etc. usually show high resistivity and high polarizability characteristics; general construction waste, high-concentration NAPLs pollutants, etc. usually show high resistivity and low polarizability characteristics; partially degraded domestic waste with active microbial activity usually shows low resistivity and high polarizability characteristics; landfill leachate, chemical production waste, inorganic salt pollutants, etc. usually show low resistivity and low polarizability characteristics. The profile inversion results of each survey line collected on site can generate a corresponding two-dimensional profile. The profile inversion results of all survey lines are integrated to perform three-dimensional interpolation to obtain the three-dimensional distribution of induced polarization parameters in the entire study area; the distribution range of the main types of landfills is cut according to the selected induced polarization signal threshold, and the small areas of scattered distribution are appropriately screened or removed. According to the designated distribution range of solid waste landfills and the induced polarization parameter thresholds of various types of solid waste landfills, the three-dimensional distribution of various types of solid waste landfills is cut out, and the volume of each type of solid waste landfill, that is, the volume of each type of solid waste landfill, is calculated.

[0071] Embodiment 2

[0072] This embodiment takes the induced polarization method survey of a solid waste landfill as an example to illustrate the method for identifying the type and determining the volume of solid waste landfill based on induced polarization signals described in Embodiment 1, and includes the following steps:

[0073] Step 1: The study area is about 950m long and 100m wide. The average thickness of the landfill is 3.5m, and the groundwater level is about 10m below the landfill. The landfill mainly includes: domestic waste and construction waste. The solid waste landfill is not equipped with an impermeable membrane and a leachate collection system, but is equipped with an aeration system to promote the biodegradation of organic matter. A total of 17 induced polarization lines were collected, namely L1-L17, of which L1-L5 are located in areas with low biodegradable waste content, L6-L9 are located in areas with high biodegradable waste content, L10 is located in the transition area between domestic waste and construction waste landfill, L11 and L12 are located at the boundary and external area of ​​the solid waste landfill, respectively. As background lines, L13-L17 are arranged perpendicular to L1-L5 and L6-L9.

[0074] Step 2: Check the abnormal data points in the measured data, remove them and then perform induced polarization data inversion. The imaging results are represented by real conductivity, imaginary conductivity and phase difference. The inversion results show that the underground structure is roughly divided into three layers. The first layer shows low conductivity and low polarization characteristics, the second layer shows high conductivity and high polarization characteristics, and the third layer shows high conductivity and medium polarization characteristics. A total of 33 points were selected to collect soil samples.

[0075] Step 3: Collect soil samples from abnormal points and test their water content, total organic carbon (TOC), iron, lead, zinc, copper content, as well as pH, conductivity, TOC, chloride ion, and sulfate ion content in the soil sample leachate. Use TOC as a characteristic pollutant and characterize the activity of microorganisms.

[0076] Step 4: Extract the real conductivity, imaginary conductivity, and phase difference parameters of the soil sample collection points in the inversion profile. The corresponding relationship between them and the TOC test results is as follows: Figures 2 - 4 As shown. The correlation coefficient r between the real conductivity σ′ and TOC TOC-σ′ =0.88, the correlation expression is TOC=629.97ln(σ′)-1213.1, the determination coefficient R 2 =0.9823, the best fitting degree. Correlation coefficient between imaginary conductivity σ″ and TOC r TOC-σ″ =0.85, the correlation expression is TOC = 450.49ln(σ″) + 1311.9, the determination coefficient R 2 =0.9346, the fitting degree is second. Phase difference Correlation coefficient with TOC The correlation expression is Coefficient of determination R 2 = 0.7038, and the fitting degree is relatively poor.

[0077] Step Five: Based on the inversion results of the comprehensive sounding lines and the test results of soil samples, select the real part conductivity, imaginary part conductivity, and TOC content as the indicators for identifying the types of landfill waste and determining the volume of landfill waste. Specific thresholds are as Figure 5 shown:[[]]END]]

[0078] (1) σ′ < 40 mS / m, σ″ < 1 mS / m, TOC < 1000 mg / kg, construction waste;

[0079] (2) 40 mS / m < σ′ < 80 mS / m, 1 mS / m < σ″ < 3 mS / m, 1000 mg / kg < TOC < 1500 mg / kg, domestic waste with low water content;

[0080] (3) 80 mS / m < σ′ < 200 mS / m, 3 mS / m < σ″ < 10 mS / m, 1500 mg / kg < TOC < 2000 mg / kg, domestic waste with high water content;

[0081] (4) σ′ > 200 mS / m, σ″ > 10 mS / m, TOC > 2000 mg / kg, microbial active area.

[0082] Step Six: The profile inversion results of each sounding line collected on-site can generate a two-dimensional profile. By synthesizing the profile inversion results of all sounding lines, three-dimensional interpolation is performed to obtain the three-dimensional distribution of induced polarization parameters in the entire study area; that is, the three-dimensional distributions of real part conductivity, imaginary part conductivity, and phase difference in the entire study area are obtained. According to the selected induced polarization signal threshold, the distribution ranges of the main types of landfill waste are cut. For the small scattered areas among them, appropriate screening or removal is carried out. According to the defined distribution ranges of solid waste landfill, the volumes of various types of solid waste landfill are calculated respectively.

[0083] Example Three

[0084] This example provides a system for identifying the types of solid waste landfill and determining the volume based on induced polarization signals, including:

[0085] An induced polarization and inversion module, which is configured to: arrange background sounding lines, laser polarization signals at the background sounding lines, collect induced polarization data, perform preprocessing, and then perform inversion;

[0086] An abnormal point selection module, which is configured to: select abnormal points with electrical characteristics according to the inversion results;

[0087] A collection and testing module, which is configured to: collect soil and groundwater samples at abnormal points of electrical characteristics and test the content of characteristic pollutants;

[0088] A correlation relationship establishment module, which is configured to: extract induced polarization parameters at the sampling points of soil and groundwater samples in the inversion profile, select the induced polarization parameters with a correlation coefficient greater than a set threshold with the content of characteristic pollutants, and establish a correlation relationship between the induced polarization parameters and the content of characteristic pollutants;

[0089] A threshold determination module, which is configured to: based on the correlation relationship between the induced polarization parameters and the content of characteristic pollutants, adjust and determine one or more induced polarization signal thresholds for identifying landfilled materials;

[0090] A type identification and volume determination module, which is configured to: identify the types of solid waste landfills according to the induced polarization parameters, select the distribution range of the designated solid waste landfills based on the induced polarization signal threshold, and calculate the volume of each type of solid waste landfill.

[0091] In some embodiments, the induced polarization and inversion module is further configured to: when collecting induced polarization data, select a survey line position as the background survey line according to the preliminary survey data of the research area in the early stage. According to the on-site induced polarization signal collection process, adjust the survey line layout plan synchronously at any time, and encrypt the survey lines in potential key pollution areas by 2-3 times.

[0092] In some embodiments, the induced polarization and inversion module is further configured to: adopt a data collection method with separated supply and measurement cables to reduce the electrode polarization phenomenon and electromagnetic coupling effect. At the same time, use stainless steel electrodes as the power supply electrodes and non-polarizable electrodes as the measurement electrodes to ensure the quality of the data signal.

[0093] In some embodiments, the induced polarization and inversion module is further configured to: before inversion, false or mutant abnormal data with large values generated by external interference or poor electrode grounding, etc., need to be removed and interpolated and replaced to eliminate or reduce its adverse impact on the inversion result.

[0094] In some embodiments, the abnormal point selection module is further configured to: when selecting abnormal points of electrical characteristics, it is necessary to compare with the inversion results of the background survey line profile and focus on delineating the regions with high resistivity and high polarization rate, high resistivity and low polarization rate, low resistivity and high polarization rate, and low resistivity and low polarization rate that are clustered and distributed.

[0095] In some embodiments, the abnormal point selection module is further configured to: control the number of boreholes, and each borehole should pass through as many abnormal points of electrical characteristics as possible. At the same time, select a background point on the background survey line as a comparison for the pollution points.

[0096] In some embodiments, the acquisition and analysis module is further configured to: when collecting soil and groundwater samples at abnormal points, if groundwater is exposed during drilling, the salinity needs to be measured on-site and used as a control for the inversion results. The selected characteristic pollutants need to refer to the preliminary investigation data of the research area to determine the types of inorganic salts, heavy metals, organic substances, etc. to be analyzed. Standardize the whole process of soil and groundwater sample collection, preservation, transfer, and analysis to ensure the authenticity and referenceability of the test data.

[0097] In some embodiments, the correlation relationship establishment module is further configured to: when establishing the correlation relationship between induced polarization parameters and the content of characteristic pollutants, the selection of induced polarization parameters depends on the selection of the data inversion model, including complex resistivity amplitude, complex conductivity amplitude, real part conductivity, imaginary part conductivity, polarizability, and phase difference. Extract the induced polarization parameters at the soil and groundwater sample collection points from the inversion profile. Calculate the correlation coefficient between the induced polarization parameters and the content of characteristic pollutants, select 1-2 induced polarization parameters with stronger correlation, and establish the correlation relationship between the two.

[0098] In some embodiments, the threshold determination module is further configured to: when delimiting the induced polarization signal threshold for identifying landfills, it is necessary to comprehensively consider the inversion results of all survey lines and preliminarily delimit the signal threshold for potential landfills. Compare the content of characteristic pollutants at all points, and screen out the range of induced polarization parameters corresponding to the background value concentration and risk value concentration. Adjust and determine one or more induced polarization signal thresholds for identifying landfills by integrating the inversion results of the survey lines and the analysis results of soil and groundwater samples.

[0099] In some embodiments, the type identification and volume determination module is further configured to: when identifying the main types of solid waste landfills based on induced polarization signals, construction waste mixed with a large amount of metallic iron, low-concentration NAPLs pollutants, etc. usually exhibit characteristics of high resistivity and high polarizability; general construction waste, high-concentration NAPLs pollutants, etc. usually exhibit characteristics of high resistivity and low polarizability; partially degraded domestic waste with active microbial activity usually exhibits characteristics of low resistivity and high polarizability; leachate, chemical production waste, inorganic salt pollutants, etc. usually exhibit characteristics of low resistivity and low polarizability. The inversion result of each survey line collected on-site can generate a two-dimensional profile. Integrate the inversion results of all survey lines and perform three-dimensional interpolation to obtain the three-dimensional distribution of induced polarization parameters in the entire research area; cut the distribution range of the main types of landfills according to the selected induced polarization signal threshold, and appropriately screen or remove the small scattered areas. Calculate the volume of each type of solid waste landfill according to the delimited distribution range of solid waste landfills.

[0100] The present invention studies the induced polarization data collected in the research area through inversion analysis, and specifically tests the soil and groundwater samples at the abnormal points of electrical properties, so as to establish the correlation between the induced polarization parameters and the content of characteristic pollutants, providing technical support for the accurate characterization of solid waste landfills. This method is simple to operate and widely applicable, can accurately characterize the heterogeneity of underground porous media, accurately identify the types of solid waste landfills, locate their ranges and calculate their volumes, providing a basis and comprehensive technical guarantee for the formulation of risk control and pollution remediation plans as well as ecological environment prevention and control, and effectively saving economic costs.

[0101] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for identifying the type and volume of solid waste landfill based on induced polarization signals, characterized in that: Including: Laying out background survey lines, obtaining laser polarization signals at the background survey lines, collecting induced polarization data, preprocessing it, and then performing inversion; Selecting abnormal points of electrical property characteristics according to the inversion results; The abnormal points of electrical property characteristics include high resistivity and high polarization rate regions, high resistivity and low polarization rate regions, low resistivity and high polarization rate regions, and low resistivity and low polarization rate regions; Collecting soil and groundwater samples at the abnormal points of electrical property characteristics and analyzing the content of characteristic pollutants; Extracting the induced polarization parameters of the soil and groundwater sample collection points in the inversion profile, selecting the induced polarization parameters with a correlation coefficient greater than the set threshold with the content of characteristic pollutants, and establishing the correlation between the induced polarization parameters and the content of characteristic pollutants; Based on the correlation between the induced polarization parameters and the content of characteristic pollutants, adjusting and determining one or more induced polarization signal thresholds for identifying landfilled materials; Identifying the types of solid waste landfills according to the induced polarization parameters, selecting the distribution range of the designated solid waste landfills based on the induced polarization signal threshold, and calculating the volume of each type of solid waste landfill; According to the distribution range of the designated solid waste landfills and the induced polarization parameter thresholds of each type of solid waste landfill, cutting out the three-dimensional distribution of each type of solid waste landfill and calculating the volume of each type of solid waste landfill, that is, the volume of each type of solid waste landfill; Selecting real part conductivity, imaginary part conductivity, and the content of characteristic pollutants as indicators for identifying the types of landfills and determining the volume of landfills; (1) σ′ < 40 mS / m, σ″ < 1 mS / m, TOC < 1000 mg / kg, construction waste; (2) 40 mS / m < σ′ < 80 mS / m, 1 mS / m < σ″ < 3 mS / m, 1000 mg / kg < TOC < 1500 mg / kg, domestic waste with low water content; (3) 80 mS / m < σ′ < 200 mS / m, 3 mS / m < σ″ < 10 mS / m, 1500 mg / kg < TOC < 2000 mg / kg, domestic waste with high water content; (4) σ′ > 200 mS / m, σ″ > 10 mS / m, TOC > 2000 mg / kg, microbial active area; Among them, σ′ represents the selected real part conductivity, σ″ represents the imaginary part conductivity, and TOC represents the content of characteristic pollutants.

2. The method for solid waste landfill type identification and volume determination based on induced polarization signals according to claim 1, characterized in that: The induced polarization parameters include: complex resistivity amplitude, complex conductivity amplitude, real part conductivity, imaginary part conductivity, polarization rate, and phase difference.

3. The method for solid waste landfill type identification and volume determination based on induced polarization signals according to claim 1, characterized in that: After selecting the abnormal points of electrical property characteristics, it also includes: controlling the number of boreholes, each borehole passing through multiple abnormal points of electrical property characteristics, and at the same time selecting a background point on the background survey line as a control for the pollution points.

4. The method for solid waste landfill type identification and volume determination based on induced polarization signals according to claim 1, characterized in that: When collecting soil and groundwater samples at the abnormal points of electrical property characteristics, if groundwater is exposed in the borehole, measuring the salinity for comparison with the inversion results.

5. The method for solid waste landfill type identification and volume determination based on induced polarization signals according to claim 1, characterized in that: The process of the preprocessing includes: removing and interpolating and replacing the false or mutated abnormal data with large magnitudes.

6. The method for solid waste landfill type identification and volume determination based on induced polarization signals according to claim 1, characterized in that: Laying out the background survey lines includes densifying the background survey lines by 2 - 3 times in the potential key pollution areas.

7. A solid waste landfill type identification and volume determination system based on induced polarization signals, characterized in that: Including: The induced polarization and inversion module is configured to: lay out background survey lines, measure induced polarization signals at the background survey lines, collect induced polarization data, perform preprocessing, and then perform inversion; The abnormal point selection module is configured to: select abnormal points of electrical property characteristics according to the inversion results; The abnormal points of electrical property characteristics include high resistivity and high polarization rate regions, high resistivity and low polarization rate regions, low resistivity and high polarization rate regions, and low resistivity and low polarization rate regions; The collection and testing module is configured to: collect soil and groundwater samples at the abnormal points of electrical property characteristics and test the content of characteristic pollutants; The correlation relationship establishment module is configured to: extract the induced polarization parameters of the soil and groundwater sample collection points in the inversion profile, select the induced polarization parameters with a correlation coefficient greater than the set threshold with the content of characteristic pollutants, and establish the correlation relationship between the induced polarization parameters and the content of characteristic pollutants; The threshold determination module is configured to: based on the correlation relationship between the induced polarization parameters and the content of characteristic pollutants, adjust and determine one or more induced polarization signal thresholds for identifying landfilled materials; The type identification and volume determination module is configured to: identify the types of solid waste landfills according to the induced polarization parameters, select the distribution range of the designated solid waste landfills based on the induced polarization signal threshold, and calculate the volume of each type of solid waste landfill; According to the distribution range of the designated solid waste landfills and the induced polarization parameter thresholds of each type of solid waste landfill, cut out the three-dimensional distribution of each type of solid waste landfill and calculate the volume of each type of solid waste landfill, that is, the volume of each type of solid waste landfill; Select the real part conductivity, imaginary part conductivity, and the content of characteristic pollutants as the indicators for identifying the types of landfills and determining the volume of landfills; (1) σ′ < 40 mS / m, σ″ < 1 mS / m, TOC < 1000 mg / kg, construction waste; (2) 40 mS / m < σ′ < 80 mS / m, 1 mS / m < σ″ < 3 mS / m, 1000 mg / kg < TOC < 1500 mg / kg, domestic waste with low water content; (3) 80 mS / m < σ′ < 200 mS / m, 3 mS / m < σ″ < 10 mS / m, 1500 mg / kg < TOC < 2000 mg / kg, domestic waste with high water content; (4) σ′ > 200 mS / m, σ″ > 10 mS / m, TOC > 2000 mg / kg, microbial active area; Wherein, σ′ represents the selected real part conductivity, σ″ represents the imaginary part conductivity, and TOC represents the content of characteristic pollutants.

Images