Multifunctional well for risk management and control of soil organic pollutants and operation method thereof

Abstract

The present application belongs to the technical field of environmental protection, and relates to a multifunctional well for risk management and control of soil organic pollutants and an operation method thereof. The multifunctional well comprises a segmented shell well pipe, a filter layer, a water stop layer and other components. The outer side of the well pipe is segmented and surrounded by the filter layer and the water stop layer according to functional requirements. The inside of the well pipe is provided with a soil gas guide pipe, a groundwater guide pipe and an online monitoring device. The upper part of the well pipe is provided with a volatile organic compound adsorption device. The top of the well pipe is a concealed well platform below the ground. The operation method comprises groundwater and soil gas monitoring, abnormality early warning and emergency disposal measures. Compared with the prior art, the multifunctional well has the advantages of integrated design, reduced repeated construction of groundwater monitoring wells and other functional wells, reduced number of well construction, shortened construction period and saved investment cost. Meanwhile, the multifunctional well can long-term online monitor pollutants, water level and pressure in the multi-phase medium, take emergency measures in time in response to abnormal conditions in the blocking structure, and effectively prevent pollution leakage risks.

Description

Technical Field

[0001] This invention belongs to the field of environmental protection technology and relates to a multifunctional well for risk management of soil organic pollutants and its operation method. Background Technology

[0002] Based on the different "pollution source-exposure pathway-receptor" pathways, soil and groundwater pollution control technologies can be divided into remediation technologies that treat pollution sources, risk management technologies that block exposure pathways, and institutional control measures that reduce receptor risks. Among these, barrier technology is a commonly used risk management technology for contaminated soil, which uses methods such as adding coverings or constructing vertical or horizontal barriers to cut off the pollutant exposure pathway and achieve the purpose of risk management.

[0003] Different types of barrier control systems can be constructed to address varying target pollutant types, hydrogeological conditions, and site environmental conditions. ZL201922479365.8 discloses an in-situ barrier control system for organically contaminated soil, comprising a relatively impermeable underground layer, organically contaminated soil, a vertical isolation wall, and a horizontal barrier layer, which can contain pollutants within the in-situ barrier control system. ZL202111429743.7 discloses a risk management method for volatile organic pollutant sites, utilizing the low permeability barrier characteristics of yellow clay, the water-resistant sealing characteristics of a two-layer fabric and one-layer membrane, and the air extraction function of a negative pressure air-conducting layer to achieve multiple barriers to volatile organic pollutants within the contaminated area. ZL202110269165.9 discloses a method for calculating the critical thickness of soil cover for soil-covered barrier measures, which can provide guidance for the design of horizontal barrier soil cover.

[0004] Barrier control measures contain pollutants within vertical and horizontal barriers. However, pollutants may migrate and diffuse in groundwater or accumulate in soil gas. Regular monitoring of pollutant concentrations in groundwater and soil gas within the barrier structure is necessary to provide data support for operation, maintenance, and early warning of the barrier's effectiveness. Furthermore, emergency measures are required to prevent pollution leakage risks when anomalies occur in groundwater and soil gas within the barrier structure, or when the effectiveness of the barrier measures decreases. However, current inventions related to barrier control primarily focus on improvements in barrier forms and materials, with limited research on monitoring and operational management of the media within the barrier structure. Summary of the Invention

[0005] The purpose of this invention is to provide a multifunctional well for risk management of soil organic pollutants and its operation method, so as to meet the needs of groundwater and soil gas monitoring, early warning and management in barrier control projects.

[0006] A multifunctional well for risk management of soil organic pollutants includes a segmented screened well pipe, a filter layer, a water-stopping layer, a soil gas conduit, a groundwater conduit, a volatile organic compound adsorption device, an online monitoring device, and a concealed well platform. The segmented screened well pipe is characterized by: the outer side of which is segmented and filled with a filter layer and a water-stopping layer according to functional requirements; the interior of the segmented screened well pipe is equipped with a soil gas conduit, a groundwater conduit, and an online monitoring device; the upper part of the segmented screened well pipe is equipped with a volatile organic compound adsorption device; and the top of the segmented screened well pipe is a concealed well platform located underground.

[0007] Furthermore, the segmented screened well pipe has a vacuum zone screened section above the groundwater level to collect soil gas, a saturated zone screened section below the groundwater level to collect groundwater, and a sedimentation pipe with a length of not less than 0.5m at the bottom, with the bottom of the sedimentation pipe sealed with a pipe plug.

[0008] Furthermore, the outer side of the screened section of the segmented screened well pipe is surrounded by a filter material layer, and the upper part of the filter material layer to the wellhead is surrounded by a water-stopping layer.

[0009] Preferably, the diameter of the segmented screened well pipe should not be less than 110mm, and the diameter should meet the installation and maintenance needs of the internal soil gas conduit, groundwater conduit, online monitoring device, etc.

[0010] Preferably, the segmented screen well pipe should be made of a suitable material according to the type of pollutant. For sites with high concentrations of chlorinated organic pollutants, stainless steel pipes should be used. The connection between well pipes should be made by threaded connection, hot melt welding or stainless steel screws. It is not advisable to use glue for bonding.

[0011] Preferably, the screened section of the segmented well pipe can be cut or perforated, and the void area should account for no less than 30% of the surface area of ​​the well pipe, while ensuring that the mechanical strength of the well pipe is not affected by the screening.

[0012] Furthermore, the filling height of the filter media layer should be 0.5m above the top of the open screen section, and the filling thickness should not be less than 0.1m. The filter media layer should preferably be selected with good sphericity and roundness, no pollution, and stable structure. The particle size of the filter media should be determined according to the particle size of the target soil layer, and should be greater than 90% of the pore diameter or slit width of the filter holes, generally with a particle size of 1-2mm.

[0013] Furthermore, the permeability coefficient of the water-stopping layer should not exceed 10. -7 For speeds of cm / s, materials such as red clay slurry, cement mortar, bentonite, and cement-bentonite slurry can be used.

[0014] Furthermore, the volatile organic compound adsorption device is located between the open screen section of the vadose zone and the top of the well pipe. It has a certain compressibility and its diameter is slightly larger than that of the well pipe. It is pressed down onto the support ring by squeezing to ensure that the soil gas can enter the wellhead area only after passing through the adsorption device. A liftable plumb line is installed at the top, and the adsorption device can be replaced by lifting the plumb line.

[0015] Preferably, the specific surface area of ​​the adsorption material in the volatile organic compound adsorption device should be greater than 900 m². 2 / g, the iodine adsorption value should be greater than 1000mg / g, and materials such as activated carbon, zeolite, and silica gel can be used.

[0016] Preferably, the support ring is made of hard plastic that will not corrode or loosen in an environment containing polluted soil gas.

[0017] Furthermore, the lower end of the soil gas conduit is set in the open screen section of the vacuum zone, and the upper end is connected to the outside of the well pipe through an external interface and a valve. The conduit is divided into two branches, with sampling ports located at the upper and lower parts of the volatile organic compound adsorption device, respectively. Each branch is equipped with an electric regulating valve. After the conduit is merged into a main pipe, it can be connected to a vacuum pump. Soil gas can be pumped to the online monitoring device by the vacuum pump. The valve is closed during non-sampling times.

[0018] Preferably, the soil gas duct should be made of corrosion-resistant inert material and should not be made of low-density polyvinyl chloride, silicone, or polyethylene pipes. The inner diameter of the pipe should not exceed 4 mm.

[0019] Furthermore, the lower end of the groundwater conduit is located in the open section of the saturated zone, and the upper end is connected to the outside of the well pipe through an external interface and valve. Corrosion-resistant and inert materials should be selected according to the type of groundwater pollutants.

[0020] Furthermore, the online monitoring device can realize online monitoring, data recording, transmission, and early warning of water level, air pressure, and pollutant concentration inside the well pipe.

[0021] Furthermore, the height of the concealed well platform should not exceed 0.1m above the ground. The annular gap between the well casing and the well pipe should not be filled with any material. The lower part of the well casing should be buried underground for fixation. The outside of the well casing should be fixed with cement and built into a slope shape. The top should be equipped with a well cover-type protective device and a special-shaped safety lock.

[0022] Preferably, the inner diameter of the well casing is 250-350 mm and the height is not greater than 500 mm.

[0023] Another objective of this invention is to provide a method for monitoring, early warning and operation management using the above-mentioned multifunctional well for risk control of soil organic pollutants, including: (1) monitoring of groundwater and soil gas; (2) early warning of monitoring anomalies; and (3) emergency response measures.

[0024] Furthermore, the groundwater and soil gas monitoring includes the following:

[0025] 1) Groundwater sampling and testing: Connect the groundwater external conduit to the groundwater conduit, use a water pump to collect groundwater samples, and test the concentration of pollutants in the groundwater;

[0026] 2) Soil gas sampling and testing: Connect the external soil gas conduit to the soil gas conduit, use a vacuum pump to collect soil gas samples, and test the concentration of pollutants in the soil gas;

[0027] 3) Online real-time monitoring: The online monitoring device built into the multi-functional well is used to monitor parameters such as water level and air pressure in the well.

[0028] Furthermore, the monitoring anomaly warning includes the following situations:

[0029] 1) Groundwater quality anomaly warning: If the concentration of pollutants in groundwater exceeds the control target value, or if the concentration of pollutants shows a continuous upward trend during two consecutive quarters of monitoring, an warning will be triggered;

[0030] 2) Early warning of abnormal soil gas quality: If the concentration of pollutants in soil gas exceeds the control target value, or if the concentration of pollutants shows a continuous upward trend during two consecutive quarters of monitoring, an early warning will be triggered.

[0031] 3) Groundwater level anomaly warning: If the groundwater level inside the functional well is higher than the water level outside the control area, or if the groundwater level shows a significant upward trend, an warning will be triggered.

[0032] 4) Early warning of abnormal soil gas pressure: If the soil gas pressure inside the functional well exceeds 101 kPa, an early warning will be triggered.

[0033] Furthermore, the emergency response measures include the following:

[0034] 1) Emergency response to abnormal groundwater quality: Connect the groundwater external conduit to the groundwater conduit, use a water pump to pump the groundwater to a mobile groundwater treatment device for treatment, or inject chemical oxidants, microbial nutrients, microbial agents, etc. into the groundwater, and continuously observe the treatment effect until the concentration of pollutants in the groundwater is lower than the control target value and shows a continuous decreasing trend in the monitoring process for four consecutive quarters.

[0035] 2) Emergency response to abnormal soil gas quality: If the soil gas quality above the volatile organic compound adsorption device is abnormal, replace the adsorption device; if the soil gas quality below the volatile organic compound adsorption device is abnormal, connect the external soil gas conduit to the soil gas conduit and use an air pump to extract the soil gas to a mobile soil gas treatment device for treatment. At the same time, implement the emergency response to abnormal groundwater quality until the concentration of pollutants in the soil gas is lower than the control target value and shows a continuous decreasing trend during four consecutive quarters of monitoring.

[0036] 3) Emergency response to abnormal groundwater level: First, investigate and repair any damage to horizontal and vertical barriers; then, connect the groundwater external conduit to the groundwater conduit and use a water pump to pump the groundwater to the surface until the groundwater level inside the functional well is lower than the water level outside the control area.

[0037] 4) Emergency response to abnormal soil gas pressure: First, investigate and analyze the cause of the abnormal soil gas pressure. If the abnormal pressure is caused by the rise in groundwater level, implement the emergency response to abnormal groundwater level as described above. If the abnormal pressure is caused by the accumulation of volatile organic compounds, implement the emergency response to abnormal soil gas quality as described above until the soil gas pressure inside the functional well returns to normal.

[0038] Compared with the prior art, the present invention has the following advantages:

[0039] This technical solution integrates multiple functions into a single multi-functional well, avoiding the duplication of constructing separate wells for different functions. Within a certain controlled area, only a small number of multi-functional wells are needed to meet various monitoring and emergency needs, significantly reducing the number of wells required compared to traditional methods. This reduction in the number of wells means fewer construction steps, thus shortening the project implementation period. It also lowers material costs such as well pipes, filter media, and water-stopping materials, as well as construction costs such as equipment rental and labor. The subsequent maintenance and management costs of multiple wells are also correspondingly reduced, effectively saving on project investment costs.

[0040] The multi-functional well, equipped with soil gas conduits, groundwater conduits, and online monitoring devices, enables long-term online monitoring of pollutant accumulation levels in multiphase media (groundwater and soil gas). It can promptly and accurately obtain information such as pollutant concentrations in groundwater and soil gas, providing data for a comprehensive understanding of the pollution situation. Simultaneously, it can monitor parameters such as water level and gas pressure within the well in real time, helping to understand dynamic changes in groundwater and soil gas pressure, thus providing important evidence for analyzing the effectiveness of containment measures and the migration patterns of groundwater and soil gas.

[0041] Corresponding emergency response measures have been developed for different abnormal situations. When groundwater quality is abnormal, it can be pumped to a mobile groundwater treatment unit or injected with chemical oxidants, microbial nutrients, or microbial agents for remediation. When soil gas quality is abnormal, if the upper part of the volatile organic compound (VOC) adsorption unit is abnormal, the adsorption unit can be replaced; if the lower part is abnormal, the soil gas is pumped to a mobile soil gas treatment unit, and this is combined with groundwater quality anomaly response measures. When groundwater level is abnormal, damage to horizontal and vertical barriers is first investigated and repaired before pumping water to lower the water level. When soil gas pressure is abnormal, the cause is first investigated and analyzed. If it is caused by a rise in groundwater level, it is addressed using groundwater level anomaly response measures; if it is caused by VOC accumulation, it is addressed using soil gas quality anomaly response measures. The treatment effect is continuously monitored during emergency response until all indicators return to normal, ensuring the emergency response measures are effective, fundamentally solving the pollution problem, and ensuring site environmental safety. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the structure of a multifunctional well for risk management of soil organic pollutants according to the present invention;

[0043] Figure 2 This is a schematic diagram illustrating the operational effect of the multi-functional well for risk management of soil organic pollutants according to the present invention;

[0044] Figure 3 This is a flowchart of the method for monitoring, early warning, and operation management of the above-mentioned multifunctional well for risk control of soil organic pollutants according to the present invention;

[0045] Figure 4 Schematic diagram of the installation of the multi-functional well in Embodiment 1 of this invention;

[0046] Figure 5 A schematic diagram of the installation of the multi-functional well in Embodiment 2 of this invention.

[0047] In the diagram: 1. Segmented screened well pipe; 2. Screened section with gas-filled zone; 3. Screened section with saturated zone; 4. Sedimentation pipe; 5. Filter media layer; 6. Water-stopping layer; 7. Soil gas conduit; 8. Groundwater conduit; 9. Volatile organic compound adsorption device; 10. Support ring; 11. Concealed well platform; 12. External groundwater conduit; 13. Water pump; 14. Online monitoring device; 15. Mobile groundwater treatment device; 16. External soil gas conduit; 17. Negative pressure sampling box; 18. Mobile soil gas treatment device; 19. Air pump. Detailed Implementation

[0048] The present invention will be further described below with reference to the accompanying drawings and embodiments. The advantages and features of the present invention will become clearer from the following description and claims. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0049] Example 1:

[0050] In this embodiment, an organically contaminated site for risk management was selected. Site investigation results showed that the main pollutants in the soil and groundwater were chlorinated hydrocarbons, DDT, benzene compounds, and polycyclic aromatic hydrocarbons. The lithology of the unconfined aquifer within the site was mainly silt, silt, and silt interbedded with silt, with good permeability and high water content. The bottom layer was a silty clay layer of a certain thickness and stable distribution, which was a good unconfined aquifer. The maximum contaminated depth of groundwater reached 40m (reaching the top of the unconfined aquifer). Existing monitoring wells and emergency response wells have limited functions and are complex to operate, which is not conducive to long-term environmental risk management.

[0051] like Figure 1 and Figure 2 As shown, a multifunctional well for risk management of soil organic pollutants provided in this embodiment includes a segmented screened well pipe 1, a filter layer 5, a water-stopping layer 6, a soil gas conduit 7, a groundwater conduit 8, a volatile organic compound adsorption device 9, an online monitoring device 14, and a concealed well platform 11, etc. Its features are: the outer side of the segmented screened well pipe 1 is segmented and filled with the filter layer 5 and the water-stopping layer 7 according to functional needs; the soil gas conduit 7, the groundwater conduit 8, the online monitoring device 14, etc. are installed inside the segmented screened well pipe 1; the volatile organic compound adsorption device 9 is installed on the upper part of the segmented screened well pipe 1; and the top of the segmented screened well pipe 1 is a concealed well platform 11 below ground. It is implemented through the following methods:

[0052] (1) Within a range of 4000m 2 Within the controlled area, surveying and setting out were conducted to determine the location of the multi-functional wells. Drilling rigs were then used to carry out the construction of the multi-functional wells, with a total of 10 multi-functional wells, each 40m deep and spaced 30m apart.

[0053] (2) The segmented screened well pipe 1 is made of stainless steel pipe. The connection between the well pipes is threaded and has a diameter of 110mm, which meets the installation and maintenance needs of the internal soil gas pipe, groundwater pipe, online monitoring device, etc.

[0054] (3) The outer side of the screened section of the segmented screened well pipe 1 is surrounded by a filter material layer 5, and the upper part of the filter material layer 5 to the wellhead is surrounded by a water-stopping layer 6. A vacuole zone screened section 2 is set above the groundwater level to collect soil gas, and a saturated zone screened section 3 is set below the groundwater level to collect groundwater. A sedimentation pipe 4 is set at the bottom, with a length of not less than 0.5m, and the bottom is sealed with a pipe plug. The screened sections of the segmented screened well pipe adopt a slit form, with the void area accounting for 50% of the surface area of ​​the well pipe, and ensuring that the mechanical strength of the well pipe is not affected by the screening.

[0055] (4) The filter media layer 5 is filled to a height of 0.6m above the top of the open screen section, with a filling thickness of 0.2m. The filter media layer 5 is made of quartz sand with a particle size of 1-2mm. The permeability coefficient of the water-stopping layer 6 is less than 10. -7 cm / s, using cement-bentonite slurry as the water-stopping material.

[0056] (5) The volatile organic compound adsorption device 9 is located between the open screen section 2 of the vadose zone and the top of the well pipe. The device diameter is slightly larger than the well pipe diameter, and it is pressed down onto the support ring 10 by compression. The support ring 10 is made of hard plastic material, which will not corrode or loosen in an environment containing polluted soil gas. The specific surface area of ​​the internal adsorption material is 1000 m². 2 / g, with an iodine adsorption value of 1200mg / g, and activated carbon was used as the adsorption material.

[0057] (6) The lower end of the soil gas conduit 7 is located in the open screen section 2 of the vacuum zone, and the upper end is connected to the outside of the well pipe through an external interface and a valve. The conduit is divided into two branches, with sampling ports located at the upper and lower parts of the volatile organic compound adsorption device 9, respectively. Each branch is equipped with an electric regulating valve. After the branches are combined into a main pipe, they can be connected to a vacuum pump. Soil gas can be pumped to the online monitoring device 14 by the vacuum pump. The valve is closed during non-sampling periods. The soil gas conduit 7 is made of corrosion-resistant inert material and has an inner diameter of 3 mm.

[0058] (7) The lower end of the groundwater conduit 8 is located in the open screen section 3 of the saturated zone, and the upper end is connected to the outside of the well pipe through an external interface and a valve. Stainless steel pipe is selected as the groundwater conduit 8 according to the type of groundwater pollutants.

[0059] (8) The online monitoring device can realize online monitoring, data recording, transmission and early warning of water level, air pressure and pollutant concentration inside the well pipe.

[0060] (9) The height of the concealed well platform 11 is flush with the ground. The annular gap between the well sleeve and the well pipe is not filled with any material. The lower part of the well sleeve is buried underground and fixed. The outside of the well sleeve is fixed with cement and built into a slope shape. The top is equipped with a well cover-type protective device and a special-shaped safety lock is installed.

[0061] (10) The monitoring functions of the multi-functional well include the following: 1) Groundwater sampling and detection: connect the groundwater external conduit 12 to the groundwater conduit 8, use the water pump 13 to collect groundwater samples, and detect the concentration of pollutants in the groundwater; 2) Soil gas sampling and detection: connect the soil gas external conduit 16 to the soil gas conduit 7, use the air pump 19 to collect soil gas samples, and detect the concentration of pollutants in the soil gas; 3) Online real-time monitoring: use the online monitoring device built into the multi-functional well to monitor parameters such as water level and air pressure in the well.

[0062] (11) The multi-functional well operates stably, and multiple indicators within the scope are continuously monitored during the risk control period to reduce the risk of leakage of polluted groundwater.

[0063] Example 2:

[0064] In Example 1, the multifunctional well was used for long-term monitoring. Example 2 of the present invention provides a method for monitoring, early warning, and operation management using the aforementioned multifunctional well for soil organic pollutant risk control. Figure 3 , Figure 4 and Figure 3 As shown, it is implemented through the following methods:

[0065] (1) During long-term monitoring using the aforementioned multifunctional well, the concentrations of pollutants in the groundwater and the concentrations of pollutants in the soil gas below the volatile organic compound adsorption device 9 showed a continuous upward trend over two consecutive quarters of monitoring, triggering groundwater quality anomaly warnings and soil gas quality anomaly warnings. Based on the anomaly warning situation, emergency response measures for groundwater quality anomalies and soil gas quality anomalies were taken respectively.

[0066] (2) Emergency response to abnormal groundwater quality: Connect the groundwater external conduit 12 to the groundwater conduit 8, use the water pump 13 to pump the groundwater to the mobile groundwater treatment device 15 for treatment, inject chemical oxidant into the groundwater at the same time, and continuously observe the treatment effect until the concentration of pollutants in the groundwater is lower than the control target value and shows a continuous decreasing trend in the monitoring process of four consecutive quarters.

[0067] (3) Emergency response to abnormal soil gas quality: Connect the soil gas external conduit 16 to the soil gas conduit 7, and use the air pump 19 to extract the soil gas to the mobile soil gas treatment device 18 for treatment. At the same time, implement the emergency response to abnormal groundwater quality until the concentration of pollutants in the soil gas is lower than the control target value and shows a continuous decreasing trend during the monitoring process of four consecutive quarters.

[0068] (4) The multifunctional well conducts long-term online monitoring of the accumulation level of pollutants in groundwater and soil gas, groundwater level, and wellhead pressure. When an abnormal warning is issued, emergency measures can be taken in a timely manner to prevent the risk of pollution leakage.

[0069] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. An operational method for a multi-functional well for risk management of soil organic pollutants inside a barrier structure, comprising: monitoring, early warning, and operational management using the multi-functional well for risk management of soil organic pollutants, including: (1) Groundwater and soil gas monitoring; (2) Monitoring and early warning of anomalies; (3) Emergency response measures; The multifunctional well includes a segmented screened well pipe (1), a filter layer (5), a water-stopping layer (6), a soil gas conduit (7), a groundwater conduit (8), a volatile organic compound adsorption device (9), an online monitoring device (14), and a concealed well platform (11). The segmented screened well pipe (1) is characterized by being surrounded and filled with a filter layer (5) and a water-stopping layer (6) in segments according to functional requirements. The segmented screened well pipe (1) is internally equipped with a soil gas conduit (7), a groundwater conduit (8), and an online monitoring device (14). A volatile organic compound adsorption device (9) is installed on the upper part of the segmented screened well pipe (1). The top of the segmented screened well pipe (1) is a concealed well platform (11) located below ground. The volatile organic compound adsorption device (9) is located between the open screen section (2) of the vadose zone and the top of the well pipe. It has a certain compressibility and the diameter of the device is larger than the diameter of the well pipe. It is pressed down to the support ring (10) by squeezing to ensure that the soil gas can enter the wellhead area only after passing through the adsorption device (9). A liftable plumb line is installed on the top, and the adsorption device (9) can be replaced by lifting the plumb line. The lower end of the soil gas conduit (7) is set in the open screen section (2) of the vacuum zone, and the upper end is connected to the outside of the well pipe through an external interface and a valve. The soil gas conduit (7) is divided into several branches, and the sampling ports are located at the upper and lower parts of the volatile organic compound adsorption device (9). Each branch is equipped with an electric regulating valve. After being merged into a main pipe, it can be connected to a vacuum pump (19). Soil gas can be sent to the online monitoring device (14) by the vacuum pump (19). The valve is closed during non-sampling time. The soil gas conduit (7) is made of corrosion-resistant inert material. The height of the concealed well platform (11) does not exceed a certain height above the ground. The annular gap between the well casing and the well pipe is not filled with any material. The lower part of the well casing is buried underground and fixed. The outside of the well casing is fixed with cement and built into a slope shape. The top is equipped with a well cover-type protective device and a special-shaped safety lock is installed. The monitoring anomaly warning includes the following situations: 1) Groundwater quality anomaly warning: If the concentration of pollutants in groundwater exceeds the control target value, or if the concentration of pollutants shows a continuous upward trend during two consecutive quarters of monitoring, an warning will be triggered; 2) Early warning of abnormal soil gas quality: If the concentration of pollutants in soil gas exceeds the control target value, or if the concentration of pollutants shows a continuous upward trend during two consecutive quarters of monitoring, an early warning will be triggered. 3) Groundwater level anomaly warning: If the groundwater level inside the functional well is higher than the water level outside the control area, or if the groundwater level shows a significant upward trend, an warning will be triggered. 4) Soil gas pressure anomaly warning: If the soil gas pressure inside the functional well exceeds 101 kPa, an early warning will be triggered; The emergency response measures include the following: 1) Emergency response to abnormal groundwater quality: Connect the groundwater external conduit to the groundwater conduit, use a water pump to pump the groundwater to a mobile groundwater treatment device for treatment, or inject chemical oxidants, microbial nutrients, and microbial agents into the groundwater, and continuously observe the treatment effect until the concentration of pollutants in the groundwater is lower than the control target value and shows a continuous decreasing trend in the monitoring process for four consecutive quarters. 2) Emergency response to abnormal soil gas quality: If the soil gas quality above the volatile organic compound adsorption device is abnormal, replace the adsorption device; if the soil gas quality below the volatile organic compound adsorption device is abnormal, connect the external soil gas conduit to the soil gas conduit and use an air pump to extract the soil gas to a mobile soil gas treatment device for treatment. At the same time, implement the emergency response to abnormal groundwater quality until the concentration of pollutants in the soil gas is lower than the control target value and shows a continuous decreasing trend during four consecutive quarters of monitoring. 3) Emergency response to abnormal groundwater level: First, investigate and repair any damage to horizontal and vertical barriers; then, connect the groundwater external conduit to the groundwater conduit and use a water pump to pump the groundwater to the surface until the groundwater level inside the functional well is lower than the water level outside the control area. 4) Emergency response to abnormal soil gas pressure: First, investigate and analyze the cause of abnormal soil gas pressure. If the abnormal pressure is caused by the rise in groundwater level, implement the emergency response to abnormal groundwater level as described above. If the abnormal pressure is caused by the accumulation of volatile organic compounds, implement the emergency response to abnormal soil gas quality as described above, until the soil gas pressure inside the functional well returns to normal.

2. The operation method of the multi-functional well for risk management of soil organic pollutants inside the barrier structure according to claim 1, characterized in that, The segmented screened well pipe (1) has a vacuum zone screened section (2) set above the groundwater level to collect soil gas, a saturated zone screened section (3) set below the groundwater level to collect groundwater, and a sedimentation pipe (4) set at the bottom. The bottom of the sedimentation pipe is sealed with a pipe plug. The segmented screened well pipe (1) has a filter material layer (5) surrounding the outside of the screened section, and a water-stopping layer (6) surrounding the upper part of the filter material layer (5) to the wellhead; the segmented screened well pipe (1) is made of a suitable well pipe material according to the type of pollutant. For sites with high concentrations of chlorinated organic pollutants, stainless steel pipes are used. The connection between well pipes is made by threaded connection, hot-melt welding or stainless steel screw fixing; the screened section of the segmented screened well pipe (1) adopts the form of slits or openings, and the void area accounts for not less than 30% of the surface area of ​​the well pipe.

3. The operation method of the multifunctional well for risk management of soil organic pollutants inside the barrier structure according to claim 1, characterized in that, The lower end of the groundwater conduit (8) is located in the open screen section (3) of the saturated zone, and the upper end is connected to the outside of the well pipe through an external interface and valve. Corrosion-resistant inert materials are selected according to the type of groundwater pollutants.

4. The operation method of the multifunctional well for risk management of soil organic pollutants inside the barrier structure according to claim 1, characterized in that, The online monitoring device (14) is used to realize online monitoring, data recording, transmission and early warning of water level, air pressure and pollutant concentration inside the well pipe.

5. The operation method of the multifunctional well for risk management of soil organic pollutants inside the barrier structure according to claim 1, characterized in that, The groundwater and soil gas monitoring includes the following: 1) Groundwater sampling and testing: Connect the groundwater external conduit to the groundwater conduit, use a water pump to collect groundwater samples, and test the concentration of pollutants in the groundwater; 2) Soil gas sampling and testing: Connect the external soil gas conduit to the soil gas conduit, use a vacuum pump to collect soil gas samples, and test the concentration of pollutants in the soil gas; 3) Online real-time monitoring: The online monitoring device built into the multi-functional well is used to monitor the water level and air pressure parameters in the well.

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