Method for correcting multi-site and multi-scale migration and transformation model of in-situ remediation of contaminated site

Abstract

The application relates to a contaminated site multi-field multi-scale in-situ remediation migration and transformation model correction method, which comprises the following steps: sending prepared contaminated soil into a centrifuge model box to carry out in-situ chemical oxidation remediation experiments under supergravity conditions, testing and collecting migration rules of secondary pollutants at different times and space scales and remediation effects of the contaminated soil, and correcting model parameters of an in-situ remediation migration and transformation model based on the migration rules and the remediation effects. Compared with the prior art, the application has the advantages of low cost, short cycle and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of contaminated soil remediation, in particular to a contaminated site multi-field multi-scale in-situ remediation migration and transformation model correction method. BACKGROUND

[0002] In-situ injection remediation is to inject medicaments into the target contaminated area through injection wells, so that the medicaments diffuse underground and contact with the pollutants in the soil and groundwater, and through oxidation, reduction or biological action, the pollutants in the soil and groundwater are converted into non-toxic or less toxic substances to the surrounding environment or human body.

[0003] The injected medicaments enter each layer of contaminated soil through the diffusion hole under the pressure action of the injection pump, form a thin layer of medicaments in the horizontal direction, and then penetrate and diffuse vertically, intersect with each other, and further cover the entire contaminated area. In the process of contaminated soil remediation, the over-addition of remediation medicaments and various types of intermediate products generated by chemical reaction or thermal decomposition can all cause secondary pollution of the remediation site. Secondary pollutants can also cause serious harm to human health and the ecological environment, for example, the use of excessive sodium persulfate in site remediation can easily cause serious acidification of soil and groundwater; excessive potassium permanganate can easily cause the site to be hardened. At present, more attention is paid to the remediation effect of the original pollutants in the site in a short period of time during the remediation of the contaminated site, and less attention is paid to the secondary pollutants generated during the remediation, so it is urgent to study the characteristics of the secondary pollution that may be formed during the remediation and the long-term remediation effect of the site.

[0004] In actual engineering, in-situ remediation technology is increasingly used. In order to improve the accuracy of in-situ remediation and reduce the generation of secondary pollution, more and more researchers use numerical simulation methods to predict and judge the effective influence radius and the distribution of pollution and medicament flow field of in-situ remediation. However, the multi-field multi-scale in-situ remediation migration and transformation model constructed at present has great differences from the actual site, the model parameters are usually empirical values, and the simulation effect cannot truly express the actual situation of in-situ remediation. At the same time, due to the over-addition of remediation medicaments and the generation of various types of intermediate products by chemical reaction or thermal decomposition, the existing in-situ remediation migration and transformation model is difficult to accurately simulate the precise pollution remediation effect diagram. If the in-situ remediation migration and transformation parameters of the contaminated site are obtained by field test method, a large amount of observation time is needed, the cycle is long, and it is difficult to determine the pollution migration and transformation characteristic parameters in a short time, so it is not convenient to design the in-situ remediation technical scheme in detail.

[0005] Based on the above existing technology, it is necessary to study the correction of the in-situ remediation migration and transformation model. SUMMARY

[0006] The present application aims to overcome the defects of the prior art and provide a low-cost and short-cycle contaminated site multi-field and multi-scale in-situ remediation migration and transformation model correction method.

[0007] The object of the present application can be achieved by the following technical solutions:

[0008] A contaminated site multi-field and multi-scale in-situ remediation migration and transformation model correction method comprises the following steps:

[0009] The prepared contaminated soil is sent into a centrifuge model box for in-situ chemical oxidation remediation test under supergravity conditions, the migration rule of secondary pollutants at different times and spatial scales and the remediation effect of the contaminated soil are tested and collected, and the model parameters of the in-situ remediation migration and transformation model are corrected based on the migration rule and the remediation effect.

[0010] Further, in the process of the in-situ chemical oxidation remediation test, a remediation agent is added into the contaminated soil through an in-situ injection device, the in-situ injection device comprises a remediation agent storage box, a first hydraulic cylinder, a second hydraulic cylinder and a plurality of injection pipes, the first hydraulic cylinder is connected with an oil supply pipe, the second hydraulic cylinder is connected with the remediation agent storage box, the second hydraulic cylinder and the plurality of injection pipes respectively, and the plurality of injection pipes are installed in the centrifuge model box.

[0011] Further, a plurality of fluid injection ports are arranged on the wall of each injection pipe.

[0012] Further, a fixing plate for fixing the injection pipes is arranged at the bottom of the centrifuge model box.

[0013] Further, the centrifuge model box satisfies the condition of Darcy number D R The remediation agent in the in-situ chemical oxidation remediation test is selected under the condition that the Darcy number D

[0014] Further, the centrifuge model box is a two-chamber model box comprising a first chamber and a second chamber, in the process of the in-situ chemical oxidation remediation test, the test conditions of the first chamber and the second chamber are controlled to be completely the same, after the centrifuge runs to a certain time, a plurality of positions in the first chamber are sampled, after sampling, the centrifuge continues to run, when running to a set time, a plurality of positions in the second chamber are sampled, and the concentration change rule of the samples at different positions and different times is obtained.

[0015] Further, the centrifuge model box is divided into a two-chamber model box by a transparent organic glass partition plate.

[0016] Further, in the in-situ chemical oxidation remediation test, the pH value and the temperature of the contaminated soil are collected by a pH sensor and a temperature sensor respectively.

[0017] Further, the pH sensor and the temperature sensor are arranged in multiple groups and are arranged at different depths of the contaminated soil in the centrifuge model box.

[0018] Further, by sampling the contaminated soil after a set test time and determining the sample composition, the migration rule of the secondary pollutants at different time and space scales and the remediation effect of the contaminated soil are obtained.

[0019] Further, the sampling is realized by the 3-hole independent sampler.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] 1. The present application combines the centrifuge model test method, is based on the principle that the chemical reaction rate and the scale effect are matched in the centrifuge model test, realizes the rapid correction of the multi-field and multi-scale in-situ remediation migration and transformation model parameters of the contaminated site, and remedies the problem that the in-situ remediation migration and transformation model parameters of the existing contaminated site are not accurate.

[0022] 2. The present application sets up an in-situ injection device to realize the injection of the remediation liquid in the in-situ chemical oxidation remediation test process, is convenient and reliable, and improves the test effectiveness.

[0023] 3. The present application designs a two-chamber model box, the same sample is used in the tests of the two chambers, the inter-group error caused by sample preparation is eliminated, the disturbance of the first sampling to the soil does not affect the second sampling, the authenticity and accuracy of the second test data are ensured, and two groups of concentration change data at different times can be obtained in one test, which significantly saves the test cost. DETAILED DESCRIPTION

[0024] Figure 1 Fig. 1 is a structural schematic view of an in-situ injection device of the present application;

[0025] Figure 2 Fig. 2 is a working schematic view of an injection pipe of the present application;

[0026] Figure 3 Fig. 3 is a structural schematic view of a two-chamber model box of the present application;

[0027] Figure 4 Fig. 4 is a sensor arrangement schematic view of the present application;

[0028] Figure 5 Fig. 5 is a schematic view of the vertical remediation effect of soil in the embodiment of the present application, wherein (5a) is an effect diagram of a 50g centrifugal acceleration operation until 7 years (prototype time), (5b) is an effect diagram of a 50g centrifugal acceleration operation until 10 years (prototype time), (5c) is an effect diagram of a 35g centrifugal acceleration operation until 7 years (prototype time), and (5d) is an effect diagram of a 35g centrifugal acceleration operation until 10 years (prototype time).

[0029] Figure 6 Fig. 6 is a schematic diagram of the soil transverse remediation effect in the embodiment of the present application, wherein (6a) is an effect diagram of 50g centrifugal acceleration operation until 7 years (prototype time), (6b) is an effect diagram of 50g centrifugal acceleration operation until 10 years (prototype time), (6c) is an effect diagram of 35g centrifugal acceleration operation until 7 years (prototype time), and (6d) is an effect diagram of 35g centrifugal acceleration operation until 10 years (prototype time). DETAILED DESCRIPTION

[0030] The present application will be described in detail below with reference to the drawings and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present application, and gives a detailed implementation and specific operation process, but the protection scope of the present application is not limited to the following embodiments.

[0031] The centrifuge model test can generate a supergravity field, can reproduce the stress level of the original site under the scale effect, can accelerate the migration of fluid in the soil, but it is difficult to solve the problem of matching the chemical reaction rate with the scale effect. The present application combines the centrifuge model test method and the pollutant unit reaction equation to develop a multi-field and multi-scale in-situ remediation migration and transformation model correction method to make up for the problem of inaccurate parameters of the existing in-situ remediation migration and transformation model of contaminated sites.

[0032] The present embodiment provides a multi-field and multi-scale in-situ remediation migration and transformation model correction method for contaminated sites, which comprises the following steps: putting the prepared contaminated soil into a centrifuge model box for in-situ chemical oxidation remediation test under supergravity conditions, testing and collecting the migration law of secondary pollutants at different time and space scales and the remediation effect of contaminated soil, and correcting the model parameters of the in-situ remediation migration and transformation model based on the migration law and the remediation effect. The above method is based on the centrifuge model test method, studies the migration law of secondary pollutants at different time and space scales and the remediation effect of contaminated soil, and realizes reliable correction of the remediation effect of the in-situ remediation migration and transformation model at a lower cost and a shorter test time.

[0033] 1. Basic principle of centrifuge test simulation

[0034] The basic principle of geotechnical centrifuge model test is to place a model made of prototype materials according to a certain scale in a high centrifugal force field generated by a centrifuge, to compensate for the loss of self-weight stress due to scale reduction by increasing the self-weight volume force of the model soil or rock mass, so that the stress state and process of the model are the same as those of the prototype.

[0035] In the centrifuge simulation test, the geometry of the model is similar to that of the prototype, and the model soil is the prototype soil. If the prototype depth is hm The unit weight of the prototype soil is γ. p Then its self-weight stress σ p It can be represented as:

[0036] σ p =γ p ·h p =ρ p ·g·h p (1)

[0037] In the formula ρ p ρ is the density of the original soil; g is the acceleration due to gravity.

[0038] If a model is made using the prototype material at a scale of 1:N and placed in a centrifugal force field, then the self-weight stress σ at the corresponding point of the model will be... m for:

[0039]

[0040] In the formula g m For the centrifugal model test acceleration, since the model soil is the prototype soil, therefore ρ p =ρ m .

[0041] Comparing equations (1) and (2), when g m When Ng is used, the model can achieve the same stress level and state as the prototype. Based on the above similarity ratios, a series of similarity ratios for parameters can be derived, including centrifugal acceleration, pollutant concentration, fluid velocity, permeability, hydraulic dispersion coefficient, molecular diffusion coefficient, macroscopic dimensions, liquid density, adsorption coefficient, chemical reaction rate, and time. The simulation time for the centrifugation test is 1 / N of the prototype's duration. 2 This means that under 50g conditions, the migration of the prototype over 10 years would only take 1.5 days, significantly accelerating the migration process of pollutants. This characteristic is the main reason why centrifuges can be used to study pollutant migration, ensuring the high efficiency of centrifugation simulation. It should be noted that the particle size should also be scaled down proportionally in the centrifugation model. However, using clay instead of sand and gravel would be clearly unsuitable because their properties are different. Therefore, the similarity ratio of the microscopic size is often considered to be 1.

[0042] Building upon Arulanandan's research, Cooke et al. proposed a ninth dimensionless number for chemical reaction processes—the chemical influence number π9, also known as the Dammel number D. R Theoretical research shows that in order to accurately simulate chemical reaction processes in centrifugation experiments, it is necessary to ensure that D... R Greater than 100.

[0043] 2. Centrifugation simulation test

[0044] The embodiment is based on an existing geotechnical centrifuge to realize in-situ chemical oxidation remediation test, and then test and collect the migration law of secondary pollutants at different time and space scales and the remediation effect of contaminated soil. In the embodiment, the maximum carrying capacity of the geotechnical centrifuge is 150 g·t, the maximum centrifugal acceleration is 200 g, the maximum load is 2 t, and the effective rotating radius is 3 m. The geotechnical centrifuge is connected with a centrifuge model box, and the model box selected in the embodiment has a length of 900.0 mm, a width of 700.0 mm and a height of 700.0 mm, as shown in Figure 3 .

[0045] The physical migration time of the centrifugal model test can be shortened to N 2 times of the prototype time, so the centrifuge test is suitable for simulating the migration problem of fluid pollutants, but the chemical reaction rate in the centrifuge test is consistent with the prototype reaction rate, so how to solve the problem of chemical reaction similarity ratio in the centrifuge test is a difficult problem of the test research.

[0046] In order to realize the chemical reaction process in the centrifugal test, it is necessary to accelerate the chemical reaction rate to meet the problem of chemical reaction similarity ratio. In actual engineering, in-situ chemical oxidation technology is used to remediate TPH contaminated soil, and the injected oxidant is sodium persulfate (Na2S2O8), and the activator is calcium hydroxide (Ca(OH)2). The reaction rate of Na2S2O8 after alkaline activation and TPH is accelerated, but it is basically considered that the reaction can be basically completed after 6 h, which is difficult to meet the requirement of D R > 100. Wu Hao found that if sodium persulfate is used as an oxidant, ferrous sulfate (Fe 2+ ) is used as an activator, and citric acid (CA) is used as a chelating agent, the remediation effect of TPH contaminated site is better, and the remediation rate is significantly improved. It can be found from the kinetics of TPH degradation in soil by Na2S2O8 / Fe 2+ / CA system that the oxidation reaction is basically completed after 30 min. According to the first-order reaction equation C=C0·e -kt , the reaction rate constant of sodium persulfate within 0-30 min is calculated as 0.0692 min -1 . In order to meet the theoretical requirement of D R > 100, the centrifuge test needs to run for more than 24 h, if a centrifugal acceleration of 50 g is used to run for 24 h, which corresponds to 7 years of prototype remediation, which meets the task requirement of the test to predict the spatial distribution of target pollutants and secondary pollutants at different stages (such as 5, 10, 15 and 20 years) in the future. And the TPH removal rate of Fe 2+ activated sodium persulfate reaches 40%, which basically does not affect the reaction product, and the secondary pollutants can still be tracked. Therefore, Na2S2O8 is used as an oxidant, and CA chelates Fe2+ The solution was used as an activator for in-situ chemical oxidation remediation of TPH-contaminated sites.

[0047] Fe 2+ The reaction process of activating Na2S2O8 with solution is as follows:

[0048]

[0049]

[0050] This shows that a certain amount of SO4 will be generated during the Na2S2O8 remediation process. 2- SO4 2- SO42 has an erosive effect on the foundation and can cause damage to the soil structure, which poses certain risks to the secondary development and utilization of the remediated site. Therefore, the post-remediation SO422 reaction must be considered. 2- Potential impacts on the soil. This experiment will use SO4. 2- SO4 was studied as a major secondary pollutant and tested. 2- The movement patterns at different time and spatial scales.

[0051] This embodiment simulates an oil-contaminated site, requiring the preparation of contaminated soil samples. The contaminant used in the experiment is national standard No. 0 diesel oil, which is a blend of straight-run diesel fraction and refined secondary-processed diesel fraction. The soil used is Fujian standard sand. Based on actual engineering pollution conditions, the initial TPH (total petroleum hydrocarbons) content was designed to be 5000 mg / kg. The contaminated soil was prepared using calculation, weighing, and stirring methods. The prepared contaminated soil was placed in plastic containers, sealed with plastic film, and allowed to stand naturally for 45 days to ensure sufficient adsorption reaction and uniform diffusion.

[0052] In actual remediation projects, injection wells are typically placed within the contaminated site. The chemical is injected into the wells under high or normal pressure to promote the gradual horizontal and vertical diffusion of the oxidizing agent until it fills the soil layer, thereby achieving a remediation effect. In the in-situ chemical oxidation remediation test of this embodiment, the remediation agent is added to the contaminated soil using an in-situ injection device. For example... Figure 1 As shown, the in-situ injection device includes a remedial agent storage tank 1, a first hydraulic cylinder 2, a second hydraulic cylinder 3, and multiple injection pipes 4. The first hydraulic cylinder 2 is connected to an oil supply pipe 5. The second hydraulic cylinder 3 is connected to the remedial agent storage tank 1, the second hydraulic cylinder 2, and the multiple injection pipes 4, respectively. The multiple injection pipes are installed inside the centrifuge model box. Specifically, the first hydraulic cylinder 2 is connected to the centrifuge's own oil supply device 8 via an oil supply pipe. The maximum pressure that the centrifuge's oil supply device can provide is 21 MPa. There are two injection pipes 4, which are connected to the second hydraulic cylinder 3 via a three-way valve 6. Preferably, each injection pipe 4 has multiple fluid nozzles on its wall to ensure that the remedial agent is evenly mixed with the soil.

[0053] Before the experiment, the repair agent is mixed with the activator and placed in the repair agent storage box 1, and then flows into the second hydraulic cylinder 3 when the injection process starts. The second hydraulic cylinder 3 is also connected with the first hydraulic cylinder 2, and the pressure provided by the oil supply device is transmitted from the first hydraulic cylinder 2 to the second hydraulic cylinder 3, and the reagent in the second hydraulic cylinder 3 is pressed into the injection pipe, and the maximum injection pressure is 7Mpa. Under the action of high pressure, the reagent is injected into the contaminated soil and fully mixed with the soil, so that the oxidizing agent fully contacts and reacts with the contaminated soil, as shown in Figure 2 .

[0054] The above in-situ injection device can be used in combination with the soil centrifuge provided by the centrifuge laboratory, the hydraulic system and the image system, and can simulate the process of injection and migration of the repair agent in the contaminated site, reveal the relationship between the liquid pressure and the influence radius, and observe the long-term migration effect of the repair agent solution.

[0055] In this embodiment, the centrifuge model box is a two-chamber model box, as shown in Figure 3 , including a first chamber and a second chamber. During the in-situ chemical oxidation repair test, the test conditions of the first chamber and the second chamber are controlled to be exactly the same. After the centrifuge runs to a certain time, samples are taken from several positions in the first chamber. After sampling, the centrifuge continues to run. When it runs to the set time, samples are taken from the same several positions in the second chamber. The concentration variation law of the samples at different positions and different times is obtained. Moreover, the disturbance caused by the first sampling to the soil does not affect the second sampling.

[0056] In the preferred embodiment, the centrifuge model box is divided into a two-chamber model box by a transparent organic glass partition plate 7. The contact part of the glass plate and the model box is fully coated with polyurethane sealant for anti-seepage, so as to ensure that there is no solute exchange through the gap during the two-part experiment.

[0057] In the preferred embodiment, as shown in Figure 3 , a fixing plate 10 for fixing the injection pipe 4 is arranged at the bottom of the centrifuge model box, so as to prevent the injection pipe from swinging greatly during the injection process and disturbing the soil. A fixing port 9 for fixing the injection pipe is installed on the fixing plate 10. The contact part of the fixing plate and the model box is also fully coated with polyurethane sealant for anti-seepage.

[0058] In order to better understand the influence of the repair process on the soil environment, pH and temperature sensors are used to detect the pH and temperature of the soil during the test, and the sensor arrangement is as shown in Figure 5 .

[0059] In this embodiment, each chamber is provided with a set of temperature sensors and pH sensors at a distance of 50 mm and 150 mm from the surface of the soil body to detect temperature and pH changes at different positions. The soil pH sensor is powered by 18-30V DC, with a range of 3-9 pH, an accuracy of ±0.3 pH, and a 0-10V voltage output. The temperature sensor uses a pressure tank type waterproof PT100 probe with a probe diameter of 30 mm, a measurement range of -50-200°C, and a polytetrafluoroethylene lead with acid and alkali resistance and resistance to various organic solvents.

[0060] In this embodiment, at each test node, the contaminated soil needs to be drilled and sampled. By sampling the contaminated soil after a set test time and measuring the composition of the sample, the migration rules of secondary pollutants at different times and spatial scales and the repair effect of the contaminated soil are obtained. Specifically, this embodiment uses a 3-hole independent sampler for sampling, with a sampling diameter of 25 mm. Each sampling can obtain three cylindrical soil samples at different heights at the same position, and the composition of each soil sample is detected.

[0061] Figure 5 and Figure 6 is the experimental effect diagram of this embodiment. From Figure 5 It can be found from (5a) and (5c) that the TPH concentration basically decreases with the increase of depth, which shows that under the action of gravity, the reagent will always move downward, resulting in that the reaction probability of the lower soil body is higher than that of the upper soil body. It can also be seen that the TPH concentration near the injection pipe area is also significantly reduced than other surrounding areas, and the overall concentration of the L3 slice farthest from the injection pipe is higher than other areas, because the reagent concentration is higher at the injection pipe. From (5b) and (5d), it can be seen that the TPH concentration is significantly reduced in 10 years than in 7 years, but a small number of areas appear a phenomenon of concentration rebound, and the overall TPH concentration tends to be consistent and is not affected by the distance from the injection pipe. The initial concentrations of the second and third groups are 3780 and 3575 mg / kg, respectively. In the 7th year, the average TPH concentration of 50g and 35g working conditions is 1644 and 1511 mg / kg, respectively, and the TPH removal rate is 56.5% and 57.7%, respectively. In the 10th year, the average TPH concentration of 50g and 35g working conditions is 1398 and 1219 mg / kg, respectively, and the TPH removal rate is 63% and 65.9%, respectively, and the concentration meets the repair requirements.

[0062] From Figure 6It can be found from (6a) and (6c) that the sulfate ion concentration is larger at the shallow surface and accumulates, while the sulfate ion concentration in other areas is relatively uniform. It can be seen from (6b) and (6d) that the ion concentration distribution is relatively uniform, and the overall concentration is lower than that in the 7th year, which shows that under the action of soil decomposition and other effects, the sulfate ion will continue to react, reducing the concentration. In the 7th year, the average concentration of sulfate ions under the conditions of 50g and 35g is 5569.5 and 6069.5mg / kg, and in the 10th year, the average concentration of sulfate ions under the conditions of 50g and 35g is 4989.8 and 5602.6mg / kg. According to the Code for Investigation of Geotechnical Engineering (GB 50021-2001 (2009)), the sulfate content within 4500-9000mg / kg belongs to the medium corrosion level. Therefore, after the repair, the sulfate ions produced in the 7th-10th year will have a medium level of corrosion effect on the concrete of the site, and the residual sulfate ions need to be repaired again to ensure the long-term repair safety of the contaminated site.

[0063] The foregoing detailed description has set forth various preferred embodiments of the application. It should be understood, however, that the disclosure is not to be limited to the details of construction or the arrangement of components set forth in the above description and illustrated in the drawings. Changes can be made in the arrangement of components or in the construction thereof, without departing from the spirit and scope of the application. Thus, various modifications and changes can be made to the present application in accordance with its teaching without departing from the spirit thereof. Therefore, it is intended that the disclosure be considered as exemplary only and not as limiting the scope of the application as set forth in the appended claims.

Claims

1. A method for correcting a migration and transformation model for multi-site, multi-scale in-situ remediation of contaminated sites, characterized in that, Includes the following steps: The prepared contaminated soil was placed in a centrifuge model chamber for in-situ chemical oxidation remediation experiments under hypergravity conditions. The transport patterns of secondary pollutants and the remediation effects on the contaminated soil at different temporal and spatial scales were tested and collected. Based on the transport patterns and remediation effects, the model parameters of the in-situ remediation migration and transformation model were corrected. During the in-situ chemical oxidation remediation experiment, a remediation agent was added to the contaminated soil using an in-situ injection device. The in-situ injection device included a remediation agent storage tank, a first hydraulic cylinder, a second hydraulic cylinder, and multiple injection pipes. The first hydraulic cylinder was connected to an oil supply pipe, and the second hydraulic cylinder was connected to the remediation agent storage tank, the first hydraulic cylinder, and the multiple injection pipes. Each injection tube has multiple fluid nozzles on its wall. The injection tubes are installed inside a centrifuge model box. A fixing plate for fixing the injection tubes is provided at the bottom of the centrifuge model box. The centrifuge model box is divided into two chambers by a transparent plexiglass partition, including a first chamber and a second chamber. During the in-situ chemical oxidation remediation experiment, the experimental conditions of the first chamber and the second chamber are kept exactly the same. After the centrifuge has run for a certain period of time, samples are taken from several locations in the first chamber. After sampling, the centrifuge continues to run. When the set time has elapsed, samples are taken from the same several locations in the second chamber to obtain the concentration change pattern of the sample at different locations at different times.

2. The method for correcting the migration and transformation model of multi-site, multi-scale in-situ remediation of contaminated sites according to claim 1, characterized in that, To meet the Dammer number D R For conditions greater than 100, select the remediation agent in the in-situ chemical oxidation remediation test.

3. The method for correcting the migration and transformation model of multi-site, multi-scale in-situ remediation of contaminated sites according to claim 1, characterized in that, In the in-situ chemical oxidation remediation experiment, pH and temperature values ​​of the contaminated soil were collected using pH and temperature sensors, respectively.

4. The method for correcting the migration and transformation model of multi-site, multi-scale in-situ remediation of contaminated sites according to claim 3, characterized in that, Multiple sets of pH and temperature sensors are installed and distributed at different depths of the contaminated soil inside the centrifuge model chamber.

5. The method for correcting the migration and transformation model of multi-site, multi-scale in-situ remediation of contaminated sites according to claim 1, characterized in that, By sampling contaminated soil after a set experimental period and measuring the composition of the samples, the transport patterns of secondary pollutants at different time and spatial scales and the remediation effect of contaminated soil were obtained.

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