Circulating well-multiphase split-flow treatment system and method for groundwater remediation

Abstract

The invention relates to the technical field of groundwater remediation, in particular to a circulating well-multiphase split-flow treatment system and method for groundwater remediation, and the system comprises a gas stripping unit, a circulating unit and a control unit; the method comprises the steps that the actual repairing range of the circulating well is determined according to the reduction amplitude of the diffusion rate of the fluorescent tracer agent; under the condition that horizontal deviation exists between the actual repairing range and the ideal repairing range, the gas injection amount of a circulating well is adjusted based on the judgment result that airflow escape exists, or the injection amount of a surfactant is adjusted based on the judgment result that the repairing range of the circulating well does not cover the low-permeability area, or the injection amount of the surfactant is adjusted based on the judgment result that the repairing range of the circulating well does not cover the low-permeability area. Under the condition that vertical deviation exists between the actual restoration range and the ideal restoration range, the gas injection temperature is adjusted based on the type of the vertical permeation barrier; and the actual concentration decline rate of the adjusted pollutants is obtained so as to optimize the actual restoration range. The remediation efficiency of underground water is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of groundwater remediation, and in particular to a circulation well-multiphase diversion treatment system and method for groundwater remediation. Background Art

[0002] Circulating well technology is currently widely used in groundwater remediation due to its in-situ treatment capabilities. However, under complex geological conditions, it faces key bottlenecks such as dynamic drift in the remediation range and mismatch between extraction parameters and the spatial distribution of pollutants. Traditional methods rely on periodic borehole sampling and static model deduction, which cannot capture the migration of remediation boundaries in real time, resulting in lagging control of key parameters such as gas injection rate and circulation flow rate. This disconnect not only significantly reduces pollutant removal flux but also leads to the risk of secondary diffusion and soaring costs due to over-remediation or blind spots in remediation.

[0003] Chinese patent application publication number: CN116854202A discloses an in-situ remediation system and remediation method for organically contaminated groundwater, relating to the technical field of groundwater pollution remediation. The system includes a circulation well main well unit, which includes a monitoring well with a flower hole provided on the pipe wall, and a water pumping pipe and a water injection pipe provided in the monitoring well; a sealing unit arranged in the monitoring well, which can seal or unseal the interior of the monitoring well, the water injection pipe is located above the sealing unit, and the water pumping pipe runs through the sealing unit; an electro-Fenton reaction unit is arranged above the sealing unit, which can generate hydrogen peroxide; an electric drive unit can drive the sealing unit to move up and down through the water pumping pipe; the invention is based on the remediation method of the above system, which can complete the sealing and unsealing of the well, thereby achieving the purpose of freely adjusting the position of the upper and lower screen sections of the well and the ratio of the screen section to the solid section; the electro-Fenton reaction unit realizes the in-situ sufficient generation of oxidizing agent through the electrochemical reaction, and realizes the efficient oxidation removal of organic pollutants in groundwater by coupling with the circulation well technology.

[0004] The following problems exist in the existing technology: the extraction parameters determine the remediation range of the circulation well, but as the remediation time continues, the remediation range of the circulation well will change under the same extraction parameters. At this time, the dynamic imbalance between the extraction parameters and the remediation range of the circulation well will lead to ineffective diffusion of the remediation agent, secondary migration of pollutants or a surge in remediation energy consumption, thereby resulting in low groundwater remediation efficiency. Summary of the Invention

[0005] To this end, the present invention provides a circulation well-multiphase diversion treatment system and method for groundwater remediation, which is used to overcome the problem of low groundwater remediation efficiency caused by dynamic imbalance between extraction parameters and remediation range of circulation wells in the prior art.

[0006] To achieve the above objectives, the present invention provides, on the one hand, a circulating well-multiphase diversion treatment method for groundwater remediation, comprising:

[0007] Determine the ideal remediation range of the circulation well based on the simulation results of the model, and determine the corresponding relationship between the ideal concentration decline rate of the pollutants and time;

[0008] The fluorescent tracer is sent into the circulation well through the gas stripping tower to determine the actual repair range of the circulation well according to the reduction degree of the diffusion rate of the fluorescent tracer;

[0009] Under the condition that there is a horizontal deviation between the actual remediation range and the ideal remediation range, whether there is airflow escape in the hyperpermeability zone is determined based on the collected concentration of volatile organic pollutants to adjust the gas injection volume of the circulation well, or whether the remediation range of the circulation well covers the hypopermeability zone is determined based on the decrease in the fluorescent tracer concentration in the hypopermeability zone to adjust the injection volume of the surfactant.

[0010] or, under the condition that there is a vertical deviation between the actual repair range and the ideal repair range, determining the type of vertical permeability barrier based on the core hardness to adjust the gas injection temperature;

[0011] The actual concentration decrease rate of the adjusted pollutants is obtained to optimize the actual remediation range.

[0012] Furthermore, the process of determining the actual repair range of the circulation well according to the magnitude of the sudden change in the diffusion rate of the fluorescent tracer includes:

[0013] Determining a plurality of annular regions with the circulation well as the center, dividing each annular region into a plurality of sub-regions, and determining the diffusion rates of the fluorescent tracer in the plurality of sub-regions;

[0014] Determining a reduction amplitude of a diffusion rate of a sub-region corresponding to an adjacent annular region, and comparing the reduction amplitude with a first preset amplitude;

[0015] Based on the comparison result that the reduction amplitude is greater than or equal to the first preset amplitude, several sub-regions with corresponding larger diffusion rates are connected to form an actual repair range of the circulation well.

[0016] Furthermore, the process of determining whether airflow escape exists according to the horizontal deviation between the actual repair range and the ideal repair range includes:

[0017] The actual repair range and the ideal repair range are overlapped with each other based on the circulation well;

[0018] Determining a fluctuation range of the collected volatile organic pollutant concentration based on a comparison result that the actual repair range exceeds the ideal repair range in the horizontal direction, and comparing the fluctuation range with a second preset range;

[0019] The presence of airflow escape is determined based on a comparison result that the fluctuation amplitude is greater than or equal to the second preset amplitude.

[0020] Furthermore, the process of determining whether the repair range of the circulation well covers the low permeability zone according to the horizontal deviation between the actual repair range and the ideal repair range includes:

[0021] The actual repair range and the ideal repair range are overlapped with each other based on the circulation well;

[0022] determining the concentration of the fluorescent tracer in the hypotonic area based on a comparison result that the actual repair range is smaller than the ideal repair range in the horizontal direction;

[0023] determining a decrease in the concentration of the fluorescent tracer in the hypotonic area and a decrease in the concentration of the fluorescent tracer in a vertically adjacent area, and comparing the decrease with a third preset amplitude;

[0024] Based on the determination result that the decrease amplitude is smaller than the third preset amplitude, it is determined that the low permeability area is not covered by the actual repair range.

[0025] Furthermore, the process of determining the type of vertical permeability barrier according to the comparison result of the actual repair range and the ideal repair range in the vertical direction includes:

[0026] The actual repair range and the ideal repair range are overlapped with each other based on the circulation well;

[0027] determining the presence of a vertical permeability barrier based on a comparison result that the actual repair range is smaller than the ideal repair range in the vertical direction;

[0028] Under the condition that the vertical permeability barrier is determined to exist, determining the hardness of the core and comparing the hardness of the core with a predetermined hardness;

[0029] Based on the comparison result that the core hardness is greater than the preset hardness, it is determined that the type of the vertical permeability barrier is a cemented zone.

[0030] Furthermore, under the condition that it is determined that there is airflow escape in the high permeability area of the circulation well, the corresponding amplitude adjustment coefficient is set according to the comparison result of the migration speed of the pollutants with the preset speed to reduce the gas injection volume.

[0031] Furthermore, under the condition that it is determined that the low permeability area is not covered by the actual repair range, a number of corresponding injection adjustment coefficients are set according to the difference between the preset amplitude and the decline amplitude to increase the injection amount of the surfactant.

[0032] Furthermore, under the condition that the vertical permeability barrier type is determined to be a cemented zone, a corresponding temperature adjustment coefficient is set according to the hardness difference between the core hardness and the preset hardness to increase the gas injection temperature.

[0033] Furthermore, the process of optimizing the actual remediation range according to the adjusted actual concentration decrease rate of the pollutants includes:

[0034] comparing the actual concentration decrease rate with a corresponding ideal concentration decrease rate;

[0035] Determining that the process of determining the actual repair range is unqualified based on a comparison result that the actual concentration decrease rate is less than the ideal concentration decrease rate;

[0036] A plurality of amplitude adjustment coefficients corresponding to the rate difference between the ideal concentration decrease rate and the actual concentration decrease rate are set to reduce the first preset amplitude.

[0037] On the other hand, the present invention also provides a treatment system using a circulating well-multiphase diversion treatment method for groundwater remediation, comprising:

[0038] A gas stripping unit comprising an injection pump for injecting gas and an extraction pump for extracting volatile organic pollutants, a gas injection pipe connected to the injection pump, and a gas extraction pipe connected to the extraction pump;

[0039] A circulation unit connected to the gas stripping unit, comprising a circulation well pipe provided with a water inlet and a water outlet, and a packer provided between the water outlets;

[0040] A control unit, connected to the circulation unit, comprising:

[0041] A data acquisition module, comprising a plurality of concentration sensors disposed at the bottom of the circulation well pipe for detecting pollutant concentrations and disposed in the exhaust pipe for detecting volatile organic pollutant concentrations, a temperature sensor disposed in the injection pipe for detecting injection gas temperature, and a plurality of fluorescence sensors disposed in groundwater for detecting fluorescent tracer signals;

[0042] a range determination module, configured to determine an ideal remediation range of the circulation well based on the simulation results of the model, and to determine a corresponding relationship between an ideal concentration decrease rate of the pollutant and time, and to determine an actual remediation range of the circulation well based on a diffusion rate of the fluorescent tracer according to the detection results of the plurality of fluorescent sensors;

[0043] A circulation determination module, which is used to determine whether there is airflow escape in the hyperpermeability zone based on the collected concentration of volatile organic pollutants, if the actual remediation range is determined to have a horizontal deviation from the ideal remediation range, or to determine whether the remediation range of the circulation well covers the hypopermeability zone based on the decrease in the fluorescent tracer concentration in the hypopermeability zone; and to determine the type of vertical permeability barrier based on core hardness, if the actual remediation range is determined to have a vertical deviation from the ideal remediation range;

[0044] A circulation adjustment module is used to adjust the gas injection volume of the circulation well based on the judgment result of the existence of air flow escape, to adjust the injection volume of the surfactant based on the judgment result that the repair range of the circulation well does not cover the low permeability area, and to adjust the gas injection temperature based on the type of vertical permeability barrier, and to optimize the actual repair range based on the actual concentration decrease rate of the pollutants after adjustment.

[0045] Compared with the prior art, the beneficial effect of the present invention is that the present invention accurately determines the actual repair range of the circulation well by injecting fluorescent tracers into the circulation well and detecting the changes in the diffusion rate of the fluorescent tracers in real time. Within the repair range, the circulation well is pumped to form a spiral three-dimensional strong displacement flow field, and the fluorescent tracer migrates rapidly under the active hydrodynamic force. Outside the repair range, the fluorescent tracer only relies on the diffusion diffusion under the natural gradient, resulting in the fluorescent tracer being driven to diffuse outward by the high flow rate inside the boundary, while the low flow rate area outside forms a blocking barrier, resulting in a steep increase in the diffusion rate gradient at the boundary, so that The reduction in diffusion rate determines the actual repair range. However, as the repair time of the circulation well increases, the repair process gradually stabilizes. According to Darcy's law and Fick's diffusion law, it can be determined that the amplitude of the diffusion rate gradient at the boundary will continue to decrease and tend to be flat. Therefore, it is necessary to continuously optimize the basis for determining the actual repair range. On the basis of determining the actual repair range, the extraction parameters are adjusted according to the comparison results between the actual repair range and the ideal repair range to make the actual repair range close to the ideal repair range to maximize the repair efficiency, thereby further improving the repair efficiency of the circulation well for groundwater.

[0046] Furthermore, under the condition that the actual remediation range is determined to be larger than the ideal remediation range in the horizontal direction, the present invention determines the fluctuation amplitude of the volatile organic pollutant concentration to determine whether airflow escape has occurred. The occurrence of airflow escape indicates that part of the extracted gas does not effectively flow through the target contaminated area to remove pollutants, but directly escapes outside the system through the existing gaps, causing the flow of the fluid to be disturbed, thereby causing the diffusion rate of the fluorescent tracer to change, causing the actual remediation range to exceed the ideal remediation range in the horizontal direction. At the same time, when airflow escape occurs, the concentration of the collected volatile organic pollutants will be significantly reduced. Therefore, it is possible to accurately identify whether airflow escape has occurred based on the fluctuation amplitude of the concentration, so as to reduce the gas injection volume under the condition that airflow escape has occurred. Airflow escape is caused by the significant pressure gradient between the gas high-pressure area formed at the gas injection end and the natural / artificial low-resistance escape channel. High gas injection volume will rapidly increase the pore gas pressure around the gas injection point. Therefore, it is necessary to reduce the gas injection volume to prevent airflow escape, thereby optimizing the actual remediation range and further improving the groundwater remediation efficiency.

[0047] Furthermore, under the condition that the actual repair range is smaller than the ideal repair range in the horizontal direction, the present invention determines the concentration decrease of the fluorescent tracer in the low permeability zone to determine whether the low permeability zone is covered. The hydraulic conductivity of the low permeability zone is low, and the flow rate of groundwater in it is extremely slow, or even almost stagnant. The circulation well mainly relies on the convection formed by pumping and reinjection to drive the water flow, bringing the pollutants out of the underground for treatment or pushing them to the reaction zone. In the low permeability zone, the convection effect is very weak, and the strong convection flow field generated by the circulation well is very likely to bypass or only partially penetrate the low permeability zone, resulting in the pollutants inside the low permeability zone cannot be effectively removed or transported. If the tracer concentration in the low permeability zone shows a significant downward trend after the circulation well has been running for a period of time, it indicates that the active flow established between the low permeability zone and the circulation well has not been effectively removed. There is an effective hydraulic connection and material exchange between the fields. The convection formed by the circulation well not only affects the edge of the low-permeability zone, but also drives the slow water flow inside the area to gradually wash out the pollutants. If the concentration of the fluorescent tracer decreases very little, it means that the hydraulic driving effect of the circulation well convection on the low-permeability zone is extremely weak or non-existent, and the low-permeability zone is basically not effectively covered by the remediation range, resulting in the low-permeability zone and the high-permeability zone being distributed horizontally, causing the actual remediation range to be smaller than the ideal remediation range in the horizontal direction. When it is determined that the low-permeability zone is not covered by the actual remediation range, the injection amount of the surfactant is increased to change the physical and chemical properties of the fluid, break through the hydraulic bottleneck of the low-permeability zone, thereby optimizing the actual remediation range and further improving the remediation efficiency of groundwater.

[0048] Furthermore, the present invention determines whether a vertical permeability barrier is required under the condition that the actual remediation range is smaller than the ideal remediation range in the vertical direction. The vertical permeability barrier will fundamentally destroy the water flow structure of the circulation well, resulting in the inability to effectively remove pollutants in the vertical direction, thereby causing the actual vertical remediation range to shrink seriously. Under the condition that the vertical permeability barrier is determined to exist, the corresponding adjustment method is determined according to the type of vertical permeability barrier, thereby optimizing the actual remediation range and further improving the groundwater remediation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a flow chart of a circulating well-multiphase diversion treatment method for groundwater remediation according to an embodiment of the present invention;

[0050] Figure 2 A flow chart for determining the actual repair range of a circulation well according to an embodiment of the present invention;

[0051] Figure 3 A flow chart for determining whether airflow escape exists according to an embodiment of the present invention;

[0052] Figure 4 This is a schematic structural diagram of a circulation well-multiphase diversion treatment system for groundwater remediation according to an embodiment of the present invention;

[0053] In the figure: 1. Injection pump, 2. Extraction pump, 3. Air injection pipe, 4. Air extraction pipe, 5. Circulation well pipe, 6. Water outlet, 7. Water inlet, 8. Packer, 9. Concentration sensor, 10. Temperature sensor. DETAILED DESCRIPTION

[0054] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are merely used to explain the present invention and are not intended to limit the present invention.

[0055] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0056] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside", and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0057] Furthermore, it should be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0058] See also Figure 1-Figure 3 As shown, Figure 1 This is a flow chart of a circulating well-multiphase diversion treatment method for groundwater remediation according to an embodiment of the present invention; Figure 2 A flow chart for determining the actual repair range of a circulation well according to an embodiment of the present invention; Figure 3 This is a flow chart for determining whether airflow escape occurs according to an embodiment of the present invention.

[0059] An embodiment of the present invention provides a circulating well-multiphase diversion treatment method for groundwater remediation, comprising:

[0060] Step S1, determining the ideal repair range of the circulation well according to the simulation results of the model, and determining the corresponding relationship between the ideal concentration decrease rate of the pollutants and time;

[0061] Step S2, sending the fluorescent tracer into the circulation well through the gas stripping tower to determine the actual repair range of the circulation well based on the reduction in the diffusion rate of the fluorescent tracer;

[0062] Step S3, under the condition that there is a horizontal deviation between the actual repair range and the ideal repair range, determining whether there is airflow escape in the hypertonic area based on the collected concentration of volatile organic pollutants to adjust the gas injection rate of the circulation well, or determining whether the repair range of the circulation well covers the hypotonic area based on the decrease in the fluorescent tracer concentration in the hypotonic area to adjust the injection rate of the surfactant,

[0063] or, under the condition that there is a vertical deviation between the actual repair range and the ideal repair range, determining the type of vertical permeability barrier based on the core hardness to adjust the gas injection temperature;

[0064] Step S4, obtaining the actual concentration decrease rate of the adjusted pollutants to optimize the actual repair range.

[0065] Specifically, the restoration process of the circulation well can be simulated by using MODFLOW software or FEFLOW software to build a hydrogeological model to simulate the groundwater flow field, and using MT3DMS software to build a solute migration model to predict the migration of pollutants, thereby determining the various parameters of the circulation well process. There is no limitation on the specific software and model, as long as it meets the simulation requirements.

[0066] Specifically, the fluorescent tracer can be sodium fluorescein, rhodamine B or rhodamine WT, and the specific type is not limited.

[0067] Specifically, the process of determining the actual repair range of the circulation well based on the magnitude of the sudden change in the diffusion rate of the fluorescent tracer includes:

[0068] Step S21, determining a plurality of annular regions with the circulation well as the center, dividing a single annular region into a plurality of sub-regions, and determining the diffusion rate of the fluorescent tracer in the plurality of sub-regions;

[0069] Step S22, determining a reduction range of the diffusion rate of the sub-regions corresponding to the adjacent annular regions, and comparing the reduction range with a first preset range;

[0070] Step S23 : Based on the comparison result that the reduction amplitude is greater than or equal to the first preset amplitude, several sub-regions with corresponding larger diffusion rates are connected to form an actual repair range of the circulation well.

[0071] Specifically, the value range of the first preset amplitude is determined according to the simulation results of the model, and is specifically set to [5%, 30%]. In the embodiment of the present invention, 20% is preferred.

[0072] It can be understood that within the repair range, the circulating well pumping forms a spiral three-dimensional strong displacement flow field, and the fluorescent tracer migrates rapidly under the active hydrodynamic force. Outside the repair range, the fluorescent tracer only relies on diffusion under the natural gradient, which causes the fluorescent tracer to diffuse outward on the inside of the boundary driven by the high flow rate, while the low flow rate area on the outside forms a blocking barrier, resulting in a sharp increase in the diffusion rate gradient at the boundary. Therefore, the actual repair range can be determined based on the reduction in the diffusion rate.

[0073] Specifically, the process of determining whether there is airflow escape based on the horizontal deviation between the actual repair range and the ideal repair range includes:

[0074] The actual repair range and the ideal repair range are overlapped with each other based on the circulation well;

[0075] Determining a fluctuation range of the collected volatile organic pollutant concentration based on a comparison result that the actual repair range exceeds the ideal repair range in the horizontal direction, and comparing the fluctuation range with a second preset range;

[0076] Determining the presence of airflow escape based on a comparison result that the fluctuation amplitude is greater than or equal to the second preset amplitude;

[0077] Based on the comparison result that the fluctuation amplitude is smaller than the second preset amplitude, it is determined that there is no airflow escape.

[0078] Specifically, the value range of the second preset amplitude is determined according to the simulation results of the model, and the specific value range is set to [20%, 50%]. In the embodiment of the present invention, 30% is preferred.

[0079] Specifically, the process of determining whether the repair range of the circulation well covers the low permeability zone according to the horizontal deviation between the actual repair range and the ideal repair range includes:

[0080] The actual repair range and the ideal repair range are overlapped with each other based on the circulation well;

[0081] determining the concentration of the fluorescent tracer in the hypotonic area based on a comparison result that the actual repair range is smaller than the ideal repair range in the horizontal direction;

[0082] determining a decrease in the concentration of the fluorescent tracer in the hypotonic area and a decrease in the concentration of the fluorescent tracer in a vertically adjacent area, and comparing the decrease with a third preset amplitude;

[0083] Determining that the low permeability area is not covered by the actual repair range based on a determination result that the decrease amplitude is less than the third preset amplitude;

[0084] Based on the determination result that the decrease amplitude is greater than or equal to the third preset amplitude, it is determined that the hypopermeability area is covered by the actual repair range.

[0085] In implementation, the comparison between the ideal repair range and the actual repair range may, for example, refer to a comparison of overlapping volumes in corresponding directions, where the ideal repair range and the actual repair range are overlapped, and the ratio of the volume of the overlapping part to the volume of the ideal repair range is determined as the degree of overlap. The ideal repair range and the actual repair range are determined to be consistent based on a comparison result where the degree of overlap is greater than or equal to 0.95, and the ideal repair range and the actual repair range are determined to be inconsistent based on a comparison result where the degree of overlap is less than 0.95. Under the condition that the ideal repair range and the actual repair range are determined to be inconsistent, the maximum absolute length difference between the ideal repair range and the actual repair range in the horizontal direction and the maximum absolute height difference between the ideal repair range and the actual repair range in the vertical direction are determined, and the maximum absolute length difference and the maximum absolute height difference are compared. Based on the comparison result that the maximum absolute length difference is greater than the maximum absolute height difference, it is determined that the actual repair range deviates from the ideal repair range in the horizontal direction, and based on the comparison result that the maximum absolute length difference is less than the maximum absolute height difference, it is determined that the actual repair range deviates from the ideal repair range in the vertical direction.

[0086] Specifically, the value range of the third preset amplitude is determined according to the simulation results of the model, and the specific value range is set to [8%, 15%]. In the embodiment of the present invention, 10% is preferred.

[0087] Specifically, the difference between the hypotonic zone and the hypertonic zone lies in the difference in permeability coefficient. The permeability coefficient is smaller (≤10 -6 The area with a high permeability coefficient (≥10 -4 m / s) is the hypertonic zone.

[0088] Specifically, the process of determining the vertical permeability barrier type based on the comparison result of the actual repair range and the ideal repair range in the vertical direction includes:

[0089] The actual repair range and the ideal repair range are overlapped with each other based on the circulation well;

[0090] determining the presence of a vertical permeability barrier based on a comparison result that the actual repair range is smaller than the ideal repair range in the vertical direction;

[0091] Determining that there is no vertical permeability barrier based on a comparison result that the actual repair range is greater than or equal to the ideal repair range in the vertical direction;

[0092] Under the condition that the vertical permeability barrier is determined to exist, determining the hardness of the core and comparing the hardness of the core with a predetermined hardness;

[0093] Determining the type of the vertical permeability barrier as a cemented zone based on a comparison result that the core hardness is greater than the preset hardness;

[0094] Based on the comparison result that the core hardness is less than or equal to the preset hardness, it is determined that the type of the vertical permeability barrier is not a cemented zone.

[0095] Specifically, the preset hardness value is 60 Shore degrees, and the specific value is determined according to objective geological conditions. For example, when the Shore hardness is greater than 60 Shore degrees, it is a siliceous / calcareous cemented layer, which is formed due to the filling of pores by SiO□ / CaCO3 in hydrothermal or buried diagenesis, and the typical rock type is quartz sandstone or limestone; when the Shore hardness is between 40 and 50 Shore degrees, it is a fault mud / mylonite, which is formed due to the enrichment of clay minerals produced by tectonic shear friction, and the typical rock type is fault zone clay breccia; when the Shore hardness is less than 30 Shore degrees, it is an undercompacted clay layer, which is formed due to the retention of high pore water in shallow buried sediments (less than 500m), and the typical rock type is soft clay and silty mudstone.

[0096] Specifically, under the condition that airflow escape exists in the high permeability area of the circulation well, the reduction range of the gas injection volume is determined according to the migration speed of the pollutants.

[0097] It is understandable that the migration rate of pollutants is determined by regularly collecting groundwater samples from monitoring wells, analyzing the changes in pollutant concentration over time, and inferring the migration rate based on the Darcy flow rate. This method is an existing technology and will not be repeated here.

[0098] Specifically, the migration speed is compared with a preset speed;

[0099] Determining to reduce the gas injection amount by a first amplitude adjustment coefficient based on a comparison result that the migration speed is greater than or equal to the preset speed;

[0100] Based on the comparison result that the migration speed is less than the preset speed, it is determined to reduce the gas injection amount by a second amplitude adjustment coefficient.

[0101] Specifically, the value range of the preset speed is set to [0.05m / day, 0.3m / day], and the embodiment of the present invention preferably is 0.1m / day; the value range of the first amplitude adjustment coefficient is set to [0.7, 0.8], and the embodiment of the present invention preferably is 0.75; the value range of the second amplitude adjustment coefficient is set to [0.81, 0.9], and the embodiment of the present invention preferably is 0.85.

[0102] Specifically, under the condition that it is determined that the low permeability area is not covered by the actual repair range, a number of corresponding injection adjustment coefficients are set according to the amplitude difference between the preset amplitude and the decline amplitude to increase the injection amount of the surfactant.

[0103] It can be understood that the surfactant is injected into the circulation well through the gas injection pipe in a pneumatic manner.

[0104] Specifically, the amplitude difference is compared with a first preset difference;

[0105] Determining, based on a comparison result that the amplitude difference is greater than or equal to the first preset difference, to increase the injection amount of the surfactant by a first injection amount adjustment coefficient;

[0106] Based on the comparison result that the amplitude difference is less than the first preset difference, it is determined to increase the injection amount of the surfactant by a second injection amount adjustment coefficient.

[0107] Specifically, the value range of the first preset difference is set to [3%, 6%], and 5% is preferred in the embodiment of the present invention; the value range of the first injection volume adjustment coefficient is set to [1.4, 1.6], and 1.5 is preferred in the embodiment of the present invention; the value range of the second injection volume adjustment coefficient is set to [1.1, 1.3], and 1.2 is preferred in the embodiment of the present invention.

[0108] Specifically, under the condition that the vertical permeability barrier type is determined to be a cemented zone, a corresponding temperature adjustment coefficient is set according to the hardness difference between the core hardness and the preset hardness to increase the gas injection temperature.

[0109] It is understandable that the geological conditions in the groundwater have been collected by various means before the circulation wells are laid, and the core hardness can be determined.

[0110] Specifically, the hardness difference is compared with a second preset difference;

[0111] determining to increase the gas injection temperature by a first temperature adjustment coefficient based on a comparison result that the hardness difference is greater than or equal to the second preset difference;

[0112] Based on the comparison result that the hardness difference is less than the second preset difference, it is determined to increase the gas injection temperature by a second temperature adjustment coefficient.

[0113] Specifically, the value range of the second preset difference is set to [0.5, 1.5], and the preferred embodiment of the present invention is 1; the value range of the first temperature adjustment coefficient is set to [1.5, 1.8], and the preferred embodiment of the present invention is 1.7; the value range of the second temperature adjustment coefficient is set to [1.2, 1.4], and the preferred embodiment of the present invention is 1.3.

[0114] Specifically, the process of optimizing the actual remediation range according to the actual concentration decrease rate of the adjusted pollutant includes:

[0115] comparing the actual concentration decrease rate with a corresponding ideal concentration decrease rate;

[0116] Determining that the process of determining the actual repair range is unqualified based on a comparison result that the actual concentration decrease rate is less than the ideal concentration decrease rate;

[0117] A plurality of amplitude adjustment coefficients corresponding to the rate difference between the ideal concentration decrease rate and the actual concentration decrease rate are set to reduce the first preset amplitude.

[0118] Specifically, the rate difference is compared with a third preset difference;

[0119] Determining to reduce the first preset amplitude by a first amplitude adjustment coefficient based on a comparison result that the rate difference is greater than or equal to the third preset difference;

[0120] Based on a comparison result that the rate difference is less than the third preset difference, it is determined to reduce the first preset amplitude by a second amplitude adjustment coefficient.

[0121] Specifically, the value range of the third preset difference is set to [0.03 mg / (L·d), 0.5 mg / (L·d)], and the embodiment of the present invention is preferably 0.04 mg / (L·d); the value range of the first amplitude adjustment coefficient is set to [0.8, 0.84], and the embodiment of the present invention is preferably 0.82; the value range of the second amplitude adjustment coefficient is set to [0.85, 0.92], and the embodiment of the present invention is preferably 0.88.

[0122] It will be appreciated that the actual concentration decrease rate is determined by regularly collecting groundwater samples using, for example, gas chromatography or liquid chromatography, and the groundwater samples are collected through monitoring wells arranged around the circulation well.

[0123] See also Figure 4 As shown, it is a structural diagram of a circulation well-multiphase diversion treatment system for groundwater remediation according to an embodiment of the present invention.

[0124] An embodiment of the present invention further provides a circulation well-multiphase diversion treatment system for groundwater remediation, comprising:

[0125] A gas stripping unit comprising an injection pump 1 for injecting gas and an extraction pump 2 for extracting volatile organic pollutants, a gas injection pipe 3 connected to the injection pump 1, and a gas extraction pipe 4 connected to the extraction pump 2;

[0126] A circulation unit connected to the gas stripping unit, comprising a circulation well pipe 5 provided with a water inlet 6 and a water outlet 7, and a packer 8 provided between the water outlets;

[0127] A control unit, connected to the circulation unit, comprising:

[0128] A data acquisition module, comprising a plurality of concentration sensors 9 disposed at the bottom of the circulation well pipe for detecting pollutant concentrations and disposed in the exhaust pipe for detecting volatile organic pollutant concentrations, a temperature sensor 10 disposed in the injection pipe for detecting the injection temperature of the gas, and a plurality of fluorescence sensors disposed in the groundwater for detecting fluorescent tracer signals;

[0129] a range determination module, configured to determine an ideal remediation range of the circulation well based on the simulation results of the model, and to determine a corresponding relationship between an ideal concentration decrease rate of the pollutant and time, and to determine an actual remediation range of the circulation well based on a diffusion rate of the fluorescent tracer according to the detection results of the plurality of fluorescent sensors;

[0130] A circulation determination module, which is used to determine whether there is airflow escape in the hyperpermeability zone based on the collected concentration of volatile organic pollutants, if the actual remediation range is determined to have a horizontal deviation from the ideal remediation range, or to determine whether the remediation range of the circulation well covers the hypopermeability zone based on the decrease in the fluorescent tracer concentration in the hypopermeability zone; and to determine the type of vertical permeability barrier based on core hardness, if the actual remediation range is determined to have a vertical deviation from the ideal remediation range;

[0131] A circulation adjustment module is used to adjust the gas injection volume of the circulation well based on the judgment result of the existence of air flow escape, to adjust the injection volume of the surfactant based on the judgment result that the repair range of the circulation well does not cover the low permeability area, and to adjust the gas injection temperature based on the type of vertical permeability barrier, and to optimize the actual repair range based on the actual concentration decrease rate of the pollutants after adjustment.

[0132] Specifically, the fluorescent sensors are not shown in the figure and are distributed throughout the groundwater.

[0133] Specifically, the sensors in the embodiments of the present invention are all commercially available products, and their specific models and parameters are not limited, as long as they can meet the detection requirements.

[0134] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. A circulating well-multiphase diversion treatment method for groundwater remediation, characterized in that: include: Determine the ideal remediation range of the circulation well based on the simulation results of the model, and determine the corresponding relationship between the ideal concentration decline rate of the pollutants and time; The fluorescent tracer is sent into the circulation well through the gas stripping tower to determine the actual repair range of the circulation well according to the reduction degree of the diffusion rate of the fluorescent tracer; Under the condition that there is a horizontal deviation between the actual remediation range and the ideal remediation range, whether there is airflow escape in the hyperpermeability zone is determined based on the collected concentration of volatile organic pollutants to adjust the gas injection volume of the circulation well, or whether the remediation range of the circulation well covers the hypopermeability zone is determined based on the decrease in the fluorescent tracer concentration in the hypopermeability zone to adjust the injection volume of the surfactant. or, under the condition that there is a vertical deviation between the actual repair range and the ideal repair range, determining the type of vertical permeability barrier based on the core hardness to adjust the gas injection temperature; The actual concentration decrease rate of the adjusted pollutants is obtained to optimize the actual remediation range.

2. The circulating well-multiphase diversion treatment method for groundwater remediation according to claim 1, characterized in that: The process of determining the actual repair extent of the circulation well based on the magnitude of the sudden change in the diffusion rate of the fluorescent tracer includes: Determining a plurality of annular regions with the circulation well as the center, dividing each annular region into a plurality of sub-regions, and determining the diffusion rates of the fluorescent tracer in the plurality of sub-regions; Determining a reduction amplitude of a diffusion rate of a sub-region corresponding to an adjacent annular region, and comparing the reduction amplitude with a first preset amplitude; Based on the comparison result that the reduction amplitude is greater than or equal to the first preset amplitude, several sub-regions with corresponding larger diffusion rates are connected to form an actual repair range of the circulation well.

3. The circulating well-multiphase diversion treatment method for groundwater remediation according to claim 2, characterized in that: The process of determining whether there is airflow escape based on the horizontal deviation between the actual repair range and the ideal repair range includes: The actual repair range and the ideal repair range are overlapped with each other based on the circulation well; Determining a fluctuation range of the collected volatile organic pollutant concentration based on a comparison result that the actual repair range exceeds the ideal repair range in the horizontal direction, and comparing the fluctuation range with a second preset range; The presence of airflow escape is determined based on a comparison result that the fluctuation amplitude is greater than or equal to the second preset amplitude.

4. The circulating well-multiphase diversion treatment method for groundwater remediation according to claim 3, characterized in that: The process of determining whether the repair range of the circulation well covers the low permeability zone according to the horizontal deviation between the actual repair range and the ideal repair range includes: The actual repair range and the ideal repair range are overlapped with each other based on the circulation well; determining the concentration of the fluorescent tracer in the hypotonic area based on a comparison result that the actual repair range is smaller than the ideal repair range in the horizontal direction; determining a decrease in the concentration of the fluorescent tracer in the hypotonic area and a decrease in the concentration of the fluorescent tracer in a vertically adjacent area, and comparing the decrease with a third preset amplitude; Based on the determination result that the decrease amplitude is smaller than the third preset amplitude, it is determined that the low permeability area is not covered by the actual repair range.

5. The circulating well-multiphase diversion treatment method for groundwater remediation according to claim 4, characterized in that: The process of determining the vertical permeability barrier type based on the comparison result of the actual repair range and the ideal repair range in the vertical direction includes: The actual repair range and the ideal repair range are overlapped with each other based on the circulation well; determining the presence of a vertical permeability barrier based on a comparison result that the actual repair range is smaller than the ideal repair range in the vertical direction; Under the condition that the vertical permeability barrier is determined to exist, determining the hardness of the core and comparing the hardness of the core with a predetermined hardness; Based on the comparison result that the core hardness is greater than the preset hardness, it is determined that the type of the vertical permeability barrier is a cemented zone.

6. The circulating well-multiphase diversion treatment method for groundwater remediation according to claim 5, characterized in that: Under the condition that airflow escape exists in the high permeability area of the circulation well, the corresponding amplitude adjustment coefficient is set to reduce the gas injection volume according to the comparison result between the migration speed of the pollutants and the preset speed.

7. The circulating well-multiphase diversion treatment method for groundwater remediation according to claim 6, characterized in that: Under the condition that it is determined that the low permeability area is not covered by the actual repair range, a number of corresponding injection adjustment coefficients are set according to the difference between the preset amplitude and the decline amplitude to increase the injection amount of the surfactant.

8. The circulating well-multiphase diversion treatment method for groundwater remediation according to claim 7, characterized in that: Under the condition that the vertical permeability barrier type is determined to be a cemented zone, a corresponding temperature adjustment coefficient is set according to the hardness difference between the core hardness and the preset hardness to increase the gas injection temperature.

9. The circulating well-multiphase diversion treatment method for groundwater remediation according to claim 8, characterized in that: The process of optimizing the actual remediation scope based on the actual concentration decline rate of the adjusted pollutant includes: comparing the actual concentration decrease rate with a corresponding ideal concentration decrease rate; Determining that the process of determining the actual repair range is unqualified based on a comparison result that the actual concentration decrease rate is less than the ideal concentration decrease rate; A plurality of amplitude adjustment coefficients corresponding to the rate difference between the ideal concentration decrease rate and the actual concentration decrease rate are set to reduce the first preset amplitude.

10. A treatment system using the circulating well-multiphase diversion treatment method for groundwater remediation according to any one of claims 1 to 9, characterized in that: include: A gas stripping unit comprising an injection pump for injecting gas and an extraction pump for extracting volatile organic pollutants, a gas injection pipe connected to the injection pump, and a gas extraction pipe connected to the extraction pump; A circulation unit connected to the gas stripping unit, comprising a circulation well pipe provided with a water inlet and a water outlet, and a packer provided between the water outlets; A control unit, connected to the circulation unit, comprising: A data acquisition module, comprising a plurality of concentration sensors disposed at the bottom of the circulation well pipe for detecting pollutant concentrations and disposed in the exhaust pipe for detecting volatile organic pollutant concentrations, a temperature sensor disposed in the injection pipe for detecting injection gas temperature, and a plurality of fluorescence sensors disposed in groundwater for detecting fluorescent tracer signals; a range determination module, configured to determine an ideal remediation range of the circulation well based on the simulation results of the model, and to determine a corresponding relationship between an ideal concentration decrease rate of the pollutant and time, and to determine an actual remediation range of the circulation well based on a diffusion rate of the fluorescent tracer according to the detection results of the plurality of fluorescent sensors; A circulation determination module, which is used to determine whether there is airflow escape in the hyperpermeability zone based on the collected concentration of volatile organic pollutants, if the actual remediation range is determined to have a horizontal deviation from the ideal remediation range, or to determine whether the remediation range of the circulation well covers the hypopermeability zone based on the decrease in the fluorescent tracer concentration in the hypopermeability zone; and to determine the type of vertical permeability barrier based on core hardness, if the actual remediation range is determined to have a vertical deviation from the ideal remediation range; A circulation adjustment module is used to adjust the gas injection volume of the circulation well based on the judgment result of the existence of air flow escape, to adjust the injection volume of the surfactant based on the judgment result that the repair range of the circulation well does not cover the low permeability area, and to adjust the gas injection temperature based on the type of vertical permeability barrier, and to optimize the actual repair range based on the actual concentration decrease rate of the pollutants after adjustment.

Images