A method and system for monitoring leachate leakage in landfills

Abstract

The present invention provides a method for monitoring leachate leakage in a landfill, the method comprising: S1, obtaining geophysical response characteristics of the migration and diffusion of pollutants in the landfill; S2, performing geochemical characteristic analysis based on the geophysical response characteristics of the migration and diffusion of pollutants; S3, combining the results of geophysical and geochemical analysis to obtain the migration and diffusion law of pollutants in the landfill. The present invention has good effect.

Description

Technical Field

[0001] The invention belongs to the technical field of engineering exploration, and in particular relates to a leachate leakage monitoring method and system for a landfill. Background Art

[0002] During the landfill process of municipal solid waste, municipal solid waste will be leached, washed and soaked by rainwater and surface runoff to form leachate. When leachate leaks, it will cause serious harm to the local environment. Traditional leachate leakage monitoring methods, such as monitoring well method and tracer method, are difficult to determine the leakage point and the geometric shape of the underground plume.

[0003] Therefore, it is necessary to design a leachate leakage monitoring method and system for landfills to solve the above-mentioned technical problems. Summary of the invention

[0004] In view of the above problems, the present invention provides a leachate leakage monitoring method for a landfill, the method comprising:

[0005] S1. Obtain geophysical response characteristics of the migration and diffusion of pollutants in landfills;

[0006] S2. Conduct geochemical characteristic analysis based on the geophysical response characteristics of the migration and diffusion of pollutants;

[0007] S3. Combine the results of geophysical and geochemical analyses to obtain the migration and diffusion patterns of pollutants in landfills.

[0008] Furthermore, the geophysical response characteristics of the migration and diffusion of pollutants include underground velocity structure and resistivity structure.

[0009] Furthermore, the method for obtaining the underground velocity structure includes:

[0010] Portable digital seismometers and node seismometers are used for data acquisition to obtain the underground velocity structure of the landfill.

[0011] Furthermore, the method for obtaining the resistivity structure includes:

[0012] A network parallel electrical instrument is used for data acquisition to obtain the resistivity structure.

[0013] The present invention also provides a leachate leakage monitoring system for a landfill, the system comprising:

[0014] The initial acquisition module is used to obtain the geophysical response characteristics of the migration and diffusion of pollutants in landfills;

[0015] The feature analysis module is used to perform geochemical feature analysis based on the geophysical response characteristics of the migration and diffusion of pollutants;

[0016] The law acquisition module is used to combine the results of geophysical and geochemical analysis to obtain the migration and diffusion laws of pollutants in landfills.

[0017] Furthermore, the geophysical response characteristics of the migration and diffusion of pollutants include underground velocity structure and resistivity structure.

[0018] Furthermore, the method for obtaining the underground velocity structure includes:

[0019] Portable digital seismographs and node-type seismographs were used for data acquisition to obtain the underground velocity structure of the landfill.

[0020] Furthermore, the method for obtaining the resistivity structure includes:

[0021] A network parallel electrical instrument is used for data acquisition to obtain the resistivity structure.

[0022] The beneficial effects of the present invention are:

[0023] (1) Establishing the dynamic evolution relationship between geophysical characteristic parameters such as resistivity and shear wave velocity and the migration and diffusion laws of landfill pollutants within the regional scope (the process of obtaining the migration and diffusion laws of landfill pollutants through geophysical response characteristics);

[0024] (2) Form an index response analysis system that combines geophysics and geochemistry.

[0025] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 A schematic flow chart of a monitoring method according to an embodiment of the present invention is shown.

[0028] Figure 2 A schematic diagram of the structure of a monitoring system according to an embodiment of the present invention is shown.

[0029] Figure 3 A schematic diagram of a monitoring method according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Geophysical exploration is a type of non-destructive detection method that has emerged recently. This method has the characteristics of simple measurement, high work efficiency, accurate detection results, and a large working and research area. The application of modern environmental geophysical methods to carry out detailed imaging of the underground structure of landfills can not only guide the collection of soil and water samples, but also identify the pollution range and internal potential migration channels of pollutants.

[0032] Surface wave exploration technology was first proposed by the United States in the 1960s and was first applied to shallow surface exploration. After decades of development and improvement, from the initial steady-state method to the current transient method, from single-channel reception to multi-channel reception, from active source to passive source, this method has become quite mature and can achieve good exploration results for shallow surface strata division. It is currently widely used in engineering surveys. The network parallel electrical method is a new type of direct current electrical method that includes the advantages of the high-density electrical method. It also has the shallow accuracy and deep reference of direct current exploration technology. It has been used in many fields such as underground pipeline exploration and hydrological engineering geology. It has been proven to be a feasible and mature geoelectric technology. Its main detection principle is to use the power supply electrode to introduce current into the ground to form an artificial electric field, and then use all the remaining electrodes as sampling electrodes for potential sampling, and finally extract data for resistivity calculation.

[0033] like Figure 1-3 As shown, the present invention provides a leachate leakage monitoring method for a landfill, characterized in that the method comprises:

[0034] S1. Obtaining geophysical response characteristics of the migration and diffusion of pollutants in a landfill, wherein the geophysical response characteristics of the migration and diffusion of pollutants include underground velocity structure and resistivity structure;

[0035] S2. Conduct geochemical characteristic analysis based on the geophysical response characteristics of the migration and diffusion of pollutants;

[0036] S3. Combine the results of geophysical and geochemical analyses to obtain the migration and diffusion patterns of pollutants in landfills.

[0037] The following is a detailed description of steps S1, S2 and S3:

[0038] In one embodiment, the acquisition of underground velocity structure and resistivity structure can be carried out in a laboratory. Therefore, in the laboratory, the acquisition of underground velocity structure is specifically as follows:

[0039] The surface wave method is used to conduct forward simulation of the landfill, specifically:

[0040] The surface wave method is used to forward simulate the domestic waste landfill and the domestic waste landfill with leakage. The Tesseral software is used to set different data parameters (location, size scale and physical and mechanical properties) for different landfills (mainly including domestic waste landfills and domestic waste landfills with leakage) (domestic waste landfills are in the non-leaking situation, and domestic waste landfills with leakage are in the leaking situation).

[0041] According to the characteristics of the geological anomaly structure on the dispersion curve, the three-dimensional velocity structure of the domestic waste landfill and the three-dimensional velocity structure of the domestic waste landfill with leakage are inverted, so as to obtain the underground velocity structure of the domestic waste landfill and the underground velocity structure of the domestic waste landfill with leakage.

[0042] Then, the different performance characteristics of geological anomalies in domestic waste landfills and geological anomalies in domestic waste landfills with leakage in different locations, different sizes and different physical and mechanical properties on the dispersion curves are analyzed and compared, so as to provide theoretical support for actual landfills and make a leakage judgment for subsequent actual landfills.

[0043] The details of obtaining the resistivity structure are as follows:

[0044] Establish a resistivity monitoring model, where the process of establishing the resistivity monitoring model is as follows:

[0045] The resistivity monitoring model established is a rectangular box experimental tank made of high-strength transparent organic glass, and the rectangular box experimental tank is filled with experimental sand with a height of 30 cm;

[0046] The experimental sand is leveled and compacted, and abnormal objects such as pipes are set in the rectangular box experimental trough. The positions of abnormal objects such as pipes and pipes are as close as possible to the actual situation of the actual landfill, and two leakage simulation points are selected at a distance of 35 cm from both side walls of the rectangular box experimental trough (that is, one of the leakage simulation points is 35 cm away from one of the side walls of the rectangular box experimental trough, and the other leakage simulation point is 35 cm away from the other side wall of the rectangular box experimental trough, and the other side wall of the rectangular box experimental trough and one of the side walls of the rectangular box experimental trough are opposite side walls).

[0047] The leachate was injected into the rectangular box test tank from two leakage points at the same time, with a total injection volume of 500 mL. In order to overcome the scale effect of the model in the laboratory, a row of 16 adjacent electrical sensors were arranged on the surface of the model sand (experimental sand), with a spacing of 5 cm.

[0048] Each electrical sensor is connected to the network parallel electrical instrument through a cable. It should be noted that background monitoring should be performed before injecting leachate to obtain the background value of the resistivity of the model sand.

[0049] Data collection starts from the injection of leachate into the leakage simulation point, and the leachate intrusion speed is controlled by a valve. The resistivity change is monitored every 1 minute to achieve dynamic monitoring of the leachate migration process.

[0050] The resistivity structure is obtained according to the resistivity monitoring model, that is, the resistivity structure is obtained according to the dynamic monitoring result of the leachate migration process.

[0051] In one embodiment, the acquisition of underground velocity structure and resistivity structure in an actual landfill (i.e., not in a laboratory, but in an actual landfill) is described as follows:

[0052] Portable digital seismographs and node seismographs are used for data acquisition to obtain the underground velocity structure of the landfill; network parallel electrical method instruments are used for data acquisition to obtain the resistivity structure, as follows:

[0053] Using a network parallel electrical instrument, 64 electrodes are arranged in a linear arrangement around the landfill, with an electrode spacing of 5m. To prevent the infinite B pole (one of the power supply electrodes) from interfering with data collection, the B pole is placed far away from the survey line (the line formed by the linear arrangement of 64 electrodes). Multiple survey lines are arranged during detection to form a three-dimensional detection. The single acquisition time is about half an hour. The acquisition results are inverted to obtain the resistivity profile of the landfill. According to the resistivity change (the resistivity change is obtained from the resistivity profile), the migration and diffusion law of pollutants in the landfill is inferred;

[0054] Portable digital seismographs are used to detect surface waves in landfills. Linear equal-spacing arrangement is adopted. Hammer source is excited on the extension line outside the arrangement of geophones. The collected waveforms are processed by software (Geogiga Seismic Pro software) to determine the stratification status of the landfill accumulation layer.

[0055] The background noise technology uses Smart Solo node seismometers to arrange dense arrays around the landfill with a spacing of 2m and a measurement time of 2 hours to extract high-frequency noise surface wave dispersion data corresponding to the shallow strata in the landfill accumulation layer, thereby obtaining the underground velocity structure.

[0056] In this outdoor application, network parallel electrical instruments, portable seismographs, and Smart Solo node-type seismic instruments are deployed around the landfill.

[0057] In step S2, geochemical characteristics analysis is performed as follows:

[0058] The grid soil sampling method is used within the pollutant diffusion range delineated by the geophysical field. The area within the delineated pollutant diffusion range is divided into 10 grid units, and 2 soil sampling points are randomly arranged in each grid unit. About 1 kg of soil samples are collected and evenly mixed at each sampling point using the quartering method. The samples are immediately sealed in sealed bags and marked with sample numbers to ensure that the samples are not contaminated.

[0059] The collected soil samples were crushed and spread flat on clean white paper. The debris in the soil samples was removed and the samples were placed in a cool and dry place in the laboratory to dry naturally. The soil samples were turned over frequently to accelerate the drying process.

[0060] Samples of landfill leachate and nearby water bodies were collected in sampling bottles. The collected water samples were sent to the laboratory as soon as possible and stored at low temperature (4°C refrigerator), and then analyzed for heavy metal content.

[0061] The heavy metal contents in landfill leachate, soil samples and nearby water samples were determined by inductively coupled plasma mass spectrometry.

[0062] In step S3, the leakage of leachate from the landfill is obtained, as follows:

[0063] By comparing the resistivity profile and shear wave velocity profile of the landfill (the shear wave velocity profile can be obtained based on the underground velocity structure) with the results of heavy metal chemical analysis (the results of analyzing the heavy metal content in the landfill leachate, soil samples and samples of nearby water bodies), conclusions were drawn (the migration and diffusion laws of pollutants in landfills).

[0064] In summary, the present invention mainly relates to geophysical exploration and geochemical analysis technology. Surface wave (forward simulation, portable seismograph and node seismograph all belong to surface wave method) exploration can obtain the shear wave velocity structure of underground medium, which has been widely used in underground cavities, karst, crust imaging and other fields. This technology uses the detected artificial or natural physical field signals without damaging the observed object, and infers the shear wave velocity structure of underground medium by inverting the surface wave dispersion curve.

[0065] The network parallel electrical method (i.e., the use of network parallel electrical method instruments) is a direct current method with distributed parallel intelligent electrode potential difference signal acquisition method as its core technical support. It is a non-destructive detection method based on the difference in conductivity between rock and soil. It studies the distribution law of conduction current in the stratum under the action of a stable current field.

[0066] In addition, the present invention also provides a leachate leakage monitoring system for a landfill, the system comprising:

[0067] The initial acquisition module is used to obtain the geophysical response characteristics of the migration and diffusion of pollutants in landfills;

[0068] The feature analysis module is used to perform geochemical feature analysis based on the geophysical response characteristics of the migration and diffusion of pollutants;

[0069] The law acquisition module is used to combine the results of geophysical and geochemical analysis to obtain the migration and diffusion laws of pollutants in landfills.

[0070] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for monitoring leachate leakage in a landfill, characterized in that: The method comprises: S1. Obtaining geophysical response characteristics of the migration and diffusion of pollutants in a landfill. The geophysical response characteristics of the migration and diffusion of pollutants include underground velocity structure and resistivity structure. The method for obtaining the underground velocity structure includes: using a portable digital seismograph and a node seismograph to collect data to obtain the underground velocity structure of the landfill. The method for obtaining the resistivity structure includes: using a network parallel electrical instrument to collect data to obtain the resistivity structure. The details are as follows: A network parallel electrical instrument was used to arrange 64 electrodes in a linear arrangement around the landfill, with an electrode spacing of 5m. Multiple survey lines were arranged during the detection to form a three-dimensional detection. The single acquisition time was half an hour, and the acquisition results were inverted to obtain the resistivity profile of the landfill. The migration and diffusion laws of pollutants in the landfill were inferred based on the resistivity changes. A portable digital seismograph was used to conduct surface wave detection of the landfill, using a linear equal-channel spacing arrangement. The hammer source was excited on the extension line outside the detector arrangement. The collected waveforms were processed by software to determine the stratification status in the landfill accumulation layer. The background noise technology used Smart Solo node seismographs to arrange dense arrays around the landfill with a spacing of 2m and a measurement time of 2 hours to extract high-frequency noise surface wave dispersion data corresponding to the shallow strata in the landfill accumulation layer, thereby obtaining the underground velocity structure. S2. According to the geophysical response characteristics of the migration and diffusion of pollutants, geochemical characteristics analysis is carried out, as follows: the grid soil sampling method is used within the pollutant diffusion range delineated by the geophysical field, and the area within the delineated pollutant diffusion range is divided into 10 grid units. Two soil sampling points are randomly arranged in each grid unit. 1 kg of soil samples are collected and mixed evenly at each sampling point using the quartering method, and immediately sealed with a sealed bag and marked with the sample number to ensure that the sample is not contaminated; the collected soil samples are crushed and spread on clean white paper, and the debris in the soil samples is removed. The soil samples are placed in a cool and dry place in the laboratory to dry naturally, and the soil samples are turned over frequently to accelerate the drying process; samples of landfill leachate and nearby water bodies are collected in sampling bottles, and the collected water samples are sent to the laboratory as soon as possible, stored at 4°C in a refrigerator, and then analyzed for heavy metal content; S3. Combine the results of geophysical and geochemical analysis to obtain the migration and diffusion patterns of pollutants in the landfill, including comparing the resistivity profile and shear wave velocity profile of the landfill with the results of heavy metal chemical analysis to obtain the migration and diffusion patterns of pollutants in the landfill. The shear wave velocity profile is obtained based on the underground velocity structure, and the heavy metal chemical analysis results are the results of analyzing the heavy metal content in the landfill leachate, soil samples and samples of nearby water bodies.

2. A leachate leakage monitoring system for a landfill, characterized in that: The system comprises: The initial acquisition module is used to obtain the geophysical response characteristics of the migration and diffusion of pollutants in the landfill. The geophysical response characteristics of the migration and diffusion of pollutants include underground velocity structure and resistivity structure. The method for obtaining the underground velocity structure includes: using a portable digital seismograph and a node seismograph to collect data to obtain the underground velocity structure of the landfill. The method for obtaining the resistivity structure includes: using a network parallel electrical instrument to collect data to obtain the resistivity structure; the details are as follows: A network parallel electrical instrument was used to arrange 64 electrodes in a linear arrangement around the landfill, with an electrode spacing of 5m. Multiple survey lines were arranged during the detection to form a three-dimensional detection. The single acquisition time was half an hour, and the acquisition results were inverted to obtain the resistivity profile of the landfill. The migration and diffusion laws of pollutants in the landfill were inferred based on the resistivity changes. A portable digital seismograph was used to conduct surface wave detection of the landfill, using a linear equal-channel spacing arrangement. The hammer source was excited on the extension line outside the detector arrangement. The collected waveforms were processed by software to determine the stratification status in the landfill accumulation layer. The background noise technology used Smart Solo node seismographs to arrange dense arrays around the landfill with a spacing of 2m and a measurement time of 2 hours to extract high-frequency noise surface wave dispersion data corresponding to the shallow strata in the landfill accumulation layer, thereby obtaining the underground velocity structure. The characteristic analysis module is used to perform geochemical characteristic analysis based on the geophysical response characteristics of the migration and diffusion of pollutants. The details are as follows: the grid soil sampling method is used within the pollutant diffusion range delineated by the geophysical field, and the area within the delineated pollutant diffusion range is divided into 10 grid units. Two soil sampling points are randomly arranged in each grid unit. 1 kg of soil samples are collected and mixed evenly at each sampling point using the quartering method, and immediately sealed with a sealed bag and marked with the sample number to ensure that the sample is not contaminated; the collected soil samples are crushed and spread on clean white paper, and the debris in the soil samples is removed. The soil samples are placed in a cool and dry place in the laboratory to dry naturally, and the soil samples are turned over frequently to accelerate the drying process; samples of landfill leachate and nearby water bodies are collected in sampling bottles, and the collected water samples are sent to the laboratory as soon as possible, stored in a refrigerator at 4°C, and then analyzed for heavy metal content; The law acquisition module is used to combine the results of geophysical and geochemical analysis to obtain the migration and diffusion laws of pollutants in the landfill, including comparing the resistivity profile and shear wave velocity profile of the landfill with the results of heavy metal chemical analysis to obtain the migration and diffusion laws of pollutants in the landfill. The shear wave velocity profile is obtained based on the underground velocity structure, and the heavy metal chemical analysis results are the results of analyzing the heavy metal content in the landfill leachate, soil samples and samples of nearby water bodies.

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