A device and method for remediating groundwater contaminated by low permeability formations

Abstract

The application provides a low-permeability stratum contaminated groundwater remediation device and method, which comprises an industrial computer, the industrial computer is used for controlling the working state of an extraction mechanism according to the information inside a pumping well, a first monitoring mechanism and a second monitoring mechanism monitor the concentration change of groundwater pollutants, and feed back the groundwater pollution condition to the industrial computer, the extraction mechanism extracts groundwater into the inside of a groundwater purifier for treatment, and a transmission mechanism changes the position of the extraction mechanism according to the distribution of the groundwater pollutants; the low-permeability stratum contaminated groundwater remediation device and method have the advantages of improving the groundwater extraction efficiency, effectively improving the extraction effect of the groundwater pollutants, and reducing the operation cost of the groundwater extraction.

Description

Technical Field

[0001] This invention relates to the field of groundwater remediation technology, and in particular to a device and method for remediating contaminated groundwater in low-permeability formations. Background Technology

[0002] Groundwater pollution is characterized by its insidious nature, long-term duration, and difficulty in reversibility. Once high concentrations of organic matter enter the groundwater environment, the costs of restoration, management, and ecological impact are extremely high, seriously threatening human health and ecological security. Therefore, risk management and remediation of polluted groundwater are of paramount importance.

[0003] Groundwater extraction is a commonly used technology for groundwater risk management and remediation. It involves extracting non-aqueous phase liquids (NAPL), dissolved organic pollutants, heavy metals, and inorganic salts from groundwater to the surface for treatment, achieving a rapid reduction in pollutant concentration. However, in low-permeability strata, continuous extraction often results in flow interruptions, leading to reduced extraction efficiency. Furthermore, the adsorption and desorption of pollutants by soil particles can cause a tailing rebound in pollutant concentration.

[0004] Therefore, it is necessary to provide a new device and method for remediating contaminated groundwater in low-permeability formations to solve the above-mentioned technical problems. Summary of the Invention

[0005] The technical problem solved by this invention is to provide a device and method for remediating contaminated groundwater in low-permeability formations that improves groundwater extraction efficiency, effectively enhances the extraction effect of groundwater pollutants, and reduces the operating cost of groundwater extraction.

[0006] To address the aforementioned technical problems, the present invention provides a low-permeability stratum contaminated groundwater remediation device comprising: an industrial control computer, which controls the working status of an extraction mechanism based on information from inside a pumping well; a first monitoring mechanism and a second monitoring mechanism monitoring changes in the concentration of groundwater pollutants and feeding back the groundwater contamination status to the industrial control computer; the extraction mechanism pumping groundwater into a groundwater purifier for treatment; and a transmission mechanism changing the position of the extraction mechanism according to the distribution of groundwater pollutants.

[0007] The extraction mechanism includes a vacuum water pump connected to the transmission mechanism. A drain hose and a first suction pipe are installed at one end of the vacuum water pump. A second suction pipe is vertically fixed to the side wall of the first suction pipe, and both the first and second suction pipes have solenoid valves installed on their side walls. A first connecting rod is fixedly connected inside the first suction pipe. A fixing block and a second connecting rod are slidably connected inside the first connecting rod. The two ends of a first spring are fixedly connected to the fixing block and the first connecting rod, respectively. The second connecting rod is rotatably connected inside the fixing block. A hemispherical mounting block is installed at one end of the second connecting rod, and a funnel-shaped rubber sleeve is installed on the side wall of the second connecting rod. An mounting ring is rotatably connected to the side wall of the first suction pipe. Multiple elastic rods are fixedly connected to the mounting ring and the side wall of the mounting block, and a layer of geotextile is fitted onto the surface of each elastic rod.

[0008] A backflushing mechanism for flushing the geotextile layer is symmetrically installed on the side wall of the first pumping pipe. The backflushing mechanism includes a backflushing pipe, with one end of the side wall of the first pumping pipe being funnel-shaped. The backflushing pipe is fixedly connected to a crossbar and a sealing block. The sealing block, which is hollow frustum-shaped, is internally connected to a ball. The two ends of the second spring are fixedly connected to the crossbar and the ball, respectively. A stop block with an arc-shaped side wall is installed at the connection between the backflushing pipe and the first pumping pipe, and the outlet of the stop block faces the interior of the geotextile layer.

[0009] Preferably, the transmission mechanism includes a steel cable, one end of which is tied to the side wall of the vacuum water pump, and the other end of which is wound around the surface of the winch. A distance sensor is installed on the side wall of the vacuum water pump. A well cover is installed on the surface of the pumping well, and the winch is placed on the surface of the well cover. A rubber pad is installed inside the well cover, and multiple sealing rings are installed equidistantly inside the rubber pad. The steel cable is slidably connected to the inside of the rubber pad and the sealing rings.

[0010] Preferably, the first monitoring mechanism includes a float plate that floats on the surface of groundwater inside the pumping well. An mounting plate is installed on the bottom surface of the float plate, and a liquid level sensor and a density meter are installed on the surface of the mounting plate. A support rod is fixedly connected at the center of the mounting plate and the float plate, and a VOC gas sensor is installed at the top of the support rod. A sliding sleeve is slidably connected to the side wall of the steel cable, and the two ends of the sliding rod are obliquely and fixedly connected to the sliding sleeve and the mounting plate.

[0011] Preferably, the second monitoring mechanism includes an installation cylinder with fences installed at both ends. One fence is connected to a float via multiple ropes, and a fixing rope is installed on the side wall of the other fence. One end of the fixing rope is fixedly connected to the vacuum water pump, and a fixed pulley is installed on the side wall of the vacuum water pump, with the fixing rope slidably connected to the side wall of the fixed pulley.

[0012] Preferably, the sidewalls of the fence are arc-shaped, and the interior of the fence has a funnel-shaped structure, with the inner diameter at the connection between the fence and the mounting cylinder being the smallest.

[0013] Preferably, a sensor group is installed inside the mounting cylinder, and the sensor group includes a densitometer, a VOCs turbidity sensor, a dissolved oxygen sensor, a temperature sensor, a pH sensor, and a conductivity sensor.

[0014] Preferably, a water pipe is installed inside the manhole cover, a drainage hose is installed at the bottom end of the water pipe, the top end of the water pipe is connected to the groundwater purifier, and a flow sensor is installed at the connection between the water pipe and the drainage hose.

[0015] Preferably, the industrial control computer has a data receiving module installed inside. The data receiving module is electrically connected to the VOC gas sensor, liquid level sensor, density meter, flow sensor, VOCs turbidity sensor, dissolved oxygen sensor, temperature sensor, pH sensor, conductivity sensor and distance sensor, respectively. The industrial control computer is also electrically connected to the winch, vacuum pump and solenoid valve.

[0016] A method for remediating contaminated groundwater in low-permeability formations specifically includes the following steps:

[0017] Step 1: Connect the device to an external power source. The first monitoring mechanism operates to monitor the water level, surface density, and volatile organic compound (VOC) content inside the pumping well. The second monitoring mechanism monitors the VOC concentration, turbidity, dissolved oxygen, temperature, pH, conductivity, and density in the groundwater. The monitored information is uploaded to the industrial control computer. The information processing module within the industrial control computer processes the information and determines the real-time pollution concentration of the groundwater, denoted as C. t The real-time groundwater level inside the pumping well is denoted as H. t The VOC gas content inside the pumping well is denoted as V. t The difference between the density at the bottom of the pumping well and the density at the surface is denoted as ρ. t ;

[0018] Step Two: The industrial control computer has an extraction parameter setting module. This module sets the groundwater remediation target value, denoted as C0, and the highest groundwater level restored inside the pumping well, denoted as H0. This highest groundwater level should be lower than the static water level inside the pumping well. The maximum VOC gas content inside the pumping well is denoted as V0, and the maximum difference between the bottom density and the surface density is denoted as ρ0. The information judgment module inside the industrial control computer continues to judge the information. When C... t <C0, Vt <V0, ρ t <ρ0, at this time each sensor is in monitoring state for groundwater; when C t >C0, H t <H0, at this time all sensors remain in monitoring mode for groundwater; when C t >C0, H t >H0, the industrial control computer operates to open the extraction mechanism, quickly pumping away the water inside the pumping well, keeping the water level inside the pumping well low, which facilitates the seepage of groundwater into the pumping well. When not in use, the extraction mechanism does not operate, reducing power consumption and saving costs.

[0019] Step 3: When ρ t >ρ0, according to H t The industrial control computer operates to open the transmission mechanism, driving the extraction mechanism to move upward inside the pumping well. When H... t When the distance between the extraction mechanism and the rising distance is 1.2 meters, the position of the extraction mechanism is fixed, and the extraction mechanism operates to remove LNAPL contaminants; when p t <ρ0, the industrial control computer operates, causing the extraction mechanism to reset;

[0020] Step 4: When V t >V0, according to H t The industrial control computer operates to open the transmission mechanism, driving the extraction mechanism to move upward inside the pumping well. When H... t When the distance between the extraction mechanism and the rising distance is 0.5 meters, the extraction mechanism is opened to remove VOC gas, reducing the VOC content in the soil. This achieves a combination of liquid and gas phase extraction, realizing multiphase extraction and enhancing the synergistic remediation of soil and groundwater. t <V0, the industrial control computer operates, causing the extraction mechanism to reset and enter the bottom of the well;

[0021] Step 5: During the up-and-down movement of the extraction mechanism, water enters the interior of the backflushing mechanism, causing the water to enter the interior of the geotextile layer and align with the backflushing, preventing the geotextile layer from becoming blocked and accelerating the pumping rate of the extraction mechanism; and when the extraction mechanism moves, it drives the second monitoring mechanism to move up and down, so that the groundwater does not constantly flush the second monitoring mechanism, removing dust from the surface of the second monitoring mechanism and improving the monitoring sensitivity of the second monitoring mechanism.

[0022] Compared with related technologies, the device and method for remediating contaminated groundwater in low-permeability formations provided by this invention have the following beneficial effects:

[0023] This invention provides a device and method for remediating contaminated groundwater in low-permeability formations. During groundwater extraction, the industrial control computer intermittently activates the extraction mechanism based on the groundwater level, rapidly pumping water out of the well to maintain a low water level and facilitate groundwater seepage. When not in use, the extraction mechanism remains inactive, reducing energy consumption and saving costs. When the LNAPL (low-permeability groundwater precipitate) on the groundwater surface is excessive, the industrial control computer activates the transmission mechanism, driving the extraction mechanism upwards within the well. This allows the extraction port to enter the LNAPL layer, rapidly removing the LNAPL from the surface.

[0024] Furthermore, because the water level inside the pumping well remains low for an extended period, the inner wall of the well and the surrounding soil are exposed. VOCs adsorbed by the soil are released into the pumping well, increasing the VOC content in the gas inside. When this reaches a critical value, the industrial control computer activates the transmission mechanism, causing the extraction mechanism to move upwards inside the pumping well. This positions the extraction port above the water surface, allowing the extraction mechanism to remove the VOC gas from the well, reducing the VOC content in the soil. The extraction of pollutants combines liquid and gas phase extraction, achieving multiphase extraction and enhancing soil-groundwater synergy. The purpose is the same as the repair; and after the gas inside the pumping well is removed, the internal pressure of the pumping well decreases, causing VOCs in the groundwater and soil to quickly converge into the pumping well, thereby accelerating the efficiency of pumping groundwater and VOCs; as the extraction mechanism moves up and down inside the groundwater, water enters the interior of the backflushing mechanism, causing the water to enter the interior of the geotextile layer for alignment and backflushing, preventing the geotextile layer from becoming blocked, and accelerating the pumping rate of the extraction mechanism; and when the extraction mechanism moves, it drives the second monitoring mechanism to move up and down, so that the groundwater continuously washes the second monitoring mechanism, removing dust from the surface of the second monitoring mechanism and improving the monitoring sensitivity of the second monitoring mechanism. Attached Figure Description

[0025] Figure 1 A schematic diagram of a preferred embodiment of the device and method for remediating contaminated groundwater in low-permeability formations provided by the present invention;

[0026] Figure 2 for Figure 1 The diagram shows an enlarged view of the structure at point A.

[0027] Figure 3 for Figure 1 The diagram shows an enlarged view of the structure at point B.

[0028] Figure 4 for Figure 1 The diagram shows an enlarged view of the structure at point C.

[0029] Figure 5 for Figure 4 The diagram shows the internal structure of the geotextile layer.

[0030] Figure 6 for Figure 4 The side view of the internal structure of the geotextile layer shown;

[0031] Figure 7 for Figure 4 The diagram shows the internal structure of the mounting cylinder.

[0032] Figure 8 This is a schematic diagram of LNAPL extraction provided by the present invention;

[0033] Figure 9 This is a schematic diagram of VOC gas extraction from inside a pumping well provided by the present invention;

[0034] Figure 10 This is a schematic diagram of the circuit structure provided by the present invention;

[0035] Figure 11 This is a schematic diagram showing the amount of groundwater extracted under two extraction methods in Embodiment 1 of the present invention.

[0036] Figure 12 This is a schematic diagram illustrating the total amount of groundwater pollutants extracted under two extraction methods in Embodiment 1 of the present invention.

[0037] Figure 13 This is a schematic diagram illustrating the groundwater level change trends under two extraction methods in Embodiment 1 of the present invention.

[0038] Numbered components in the diagram: 1. Industrial control computer; 2. Groundwater purifier; 21. Water pipe; 3. Pumping well; 31. Well cover; 4. Transmission mechanism; 41. Winch; 42. Steel cable; 43. Rubber pad; 44. Sealing ring; 45. Distance sensor; 5. First monitoring mechanism; 51. Float; 52. Support rod; 53. VOC gas sensor; 54. Mounting plate; 55. Liquid level sensor; 56. Density meter; 57. Sliding rod; 58. Sliding sleeve; 6. Extraction mechanism; 61. Vacuum water pump; 62. Drainage hose; 63. First pumping pipe; 64. Second... 65. Pumping pipe, 66. Geotextile layer, 67. Solenoid valve, 68. Elastic rod, 69. Mounting block, 60. Mounting ring, 610. First connecting rod, 611. Fixing block, 612. First spring, 613. Rubber sleeve, 614. Second connecting rod, 7. Second monitoring mechanism, 71. Mounting cylinder, 72. Fence, 73. Float, 74. Tie rope, 75. Fixing rope, 76. Fixed pulley, 77. Sensor group, 8. Backflush mechanism, 81. Backflush pipe, 82. Stop block, 83. Second spring, 84. Crossbar, 85. Clamping ball, 86. Sealing block. Detailed Implementation

[0039] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0040] Please see Figures 1-10 , Figure 1 A schematic diagram of a preferred embodiment of the device and method for remediating contaminated groundwater in low-permeability formations provided by the present invention; Figure 2 for Figure 1 The diagram shows an enlarged view of the structure at point A. Figure 3 for Figure 1 The diagram shows an enlarged view of the structure at point B. Figure 4 for Figure 1 The diagram shows an enlarged view of the structure at point C. Figure 5 for Figure 4 The diagram shows the internal structure of the geotextile layer. Figure 6 for Figure 4 The side view of the internal structure of the geotextile layer shown; Figure 7 for Figure 4 The diagram shows the internal structure of the mounting cylinder. Figure 8 This is a schematic diagram of LNAPL extraction provided by the present invention; Figure 9 This is a schematic diagram of VOC gas extraction from inside a pumping well provided by the present invention; Figure 10 This is a schematic diagram of the circuit structure provided by the present invention. The low-permeability stratum contaminated groundwater remediation device includes: an industrial control computer 1, which controls the working state of the extraction mechanism 6 based on information from the pumping well 3; a first monitoring mechanism 5 and a second monitoring mechanism 7, which monitor changes in the concentration of groundwater pollutants and feed back the groundwater contamination status to the industrial control computer 1.

[0041] The first monitoring mechanism 5 includes a float 51, which floats on the surface of groundwater inside the pumping well 3. A mounting plate 54 is installed on the bottom surface of the float 51, and a level sensor 55 and a density meter 56 are installed on the surface of the mounting plate 54. A support rod 52 is fixedly connected between the mounting plate 54 and the float 51 at their center, and a VOC gas sensor 53 is installed at the top of the support rod 52. A sliding sleeve 58 is slidably connected to the side wall of the steel cable 42, and the two ends of the sliding rod 57 are obliquely and fixedly connected to the sliding sleeve 58 and the mounting plate 54. The buoyancy of the float 51 in the water is greater than the weight of the float 51, causing the float 51 to float on the water surface. The mounting plate 54 is fixed to the bottom surface of the float 51, and the support rod 52 penetrates the center of the interior of the float 51. The density of 2 is greater than that of water, increasing the weight of the float 51 and its stability on the water surface, preventing the float 51 from swaying in the water. The float 51 moves up and down inside the pumping well 3 with the water level. The float 51 drives the sliding rod 57 and the sliding sleeve 58 to slide on the surface of the steel cable 42. The steel cable 42 is always taut, and the sliding rod 57 is tilted to facilitate the sliding of the sliding sleeve 58 on the surface of the steel cable 42, thereby further improving the stability of the float 51 in the water and preventing it from tipping over. This ensures that the level sensor 55 and the density meter 56 are always positioned at the water surface to monitor the water level and density, and that the VOC gas sensor 53 is positioned above the water surface to monitor the content of volatile organic compounds inside the pumping well 3.

[0042] The second monitoring mechanism 7 includes an installation cylinder 71, with guardrails 72 installed at both ends. One guardrail 72 is connected to a float 73 via multiple ropes 74, and a fixing rope 75 is installed on the side wall of the other guardrail 72. One end of the fixing rope 75 is fixedly connected to a vacuum water pump 61, and a fixed pulley 76 is installed on the side wall of the vacuum water pump 61, with the fixing rope 75 slidably connected to the side wall of the fixed pulley 76. A sensor group 77 is installed inside the installation cylinder 71, including a density meter 56, a VOCs turbidity sensor, a dissolved oxygen sensor, a temperature sensor, a pH sensor, a conductivity sensor, and other groundwater monitoring components. The buoyancy generated by the float 73 in the water is always greater than the downward pull it experiences, thereby ensuring the buoyancy of the float 73. The float 73 pulls the fence 72 and the fixed cylinder 71 upwards via the rope 74. The fixed rope 75 secures the fence 72 and the fixed cylinder 71. The fixed cylinder 71 is located in the water and on one side of the vacuum water pump 61. The fixed rope 75 is turned by the fixed pulley 76 and connected to the fence 72. The centers of the fixed pulley 76, the fence 72, the fixed cylinder 71, and the float 73 are on the same straight line, so that the float 73 pulls the fence 72 vertically upwards, making the fence 72 and the mounting cylinder 71 vertically located in the water. The two fences 72 protect the mounting cylinder 71, preventing other objects from contacting the mounting cylinder 71 and protecting the mounting cylinder 71 and the sensor group 77 inside it.

[0043] Water inside the pumping well 3 passes through the enclosure 72 and enters the interior of the mounting cylinder 71. The surface of the mounting cylinder 71 is provided with multiple through holes to facilitate the movement of groundwater inside the mounting cylinder 71, so that the sensor group 77 inside the mounting cylinder 71 comes into contact with the water, thereby monitoring indicators such as VOCs concentration, water turbidity, dissolved oxygen, temperature, pH, turbidity, and conductivity in the groundwater, thereby monitoring the degree of groundwater pollution.

[0044] The sensor group 77 contains a hydrometer 56, which monitors the density of the water at the bottom of the pumping well 3 and records it as the bottom density. The surface of the float 51 is also equipped with a hydrometer 56 to monitor the density of the liquid at the top of the pumping well 3 and records it as the surface density. Since LNAPL is a petroleum-based organic pollutant that floats on the water surface, and the density of LNAPL is less than that of groundwater, the presence of LNAPL on the water surface can be determined by comparing the bottom density and the surface density, thus facilitating the extraction of LNAPL pollutants from the groundwater.

[0045] The sidewalls of the fence 72 are arc-shaped, and the interior of the fence 72 has a funnel-shaped structure. The inner diameter of the connection between the fence 72 and the mounting cylinder 71 is the smallest. When the vacuum water pump 61 moves up and down in the water, the float 73 and the vacuum water pump 61 drive the fence 72 to move up and down in the water. During this process, groundwater rushes into the interior of the mounting cylinder 71 through the funnel-shaped structure of the fence 72. As the groundwater moves inside the fence 72, the space for movement gradually decreases, thereby increasing the flow velocity of the water inside the fence 72 and the mounting cylinder 71. This allows the groundwater to flow quickly over the surface of the sensor group 77, thereby washing away impurities that have settled on the surface of the sensor group 77 and improving the sensitivity of the sensor group 77.

[0046] The transmission mechanism 4 changes the position of the extraction mechanism 6 according to the distribution of groundwater pollutants; the transmission mechanism 4 includes a steel cable 42, one end of which is tied to the side wall of the vacuum pump 61, and the other end of which is wound around the surface of the winch 41, and a distance sensor 45 is installed on the side wall of the vacuum pump 61; a well cover 31 is installed on the surface of the pumping well 3, and the winch 41 is placed on the surface of the well cover 31; a rubber gasket 43 is installed inside the well cover 31, and multiple sealing rings 44 are equidistantly installed inside the rubber gasket 43, and the rubber gasket 43 and the sealing rings 44 slide inside each other. The steel cable 42 is dynamically connected. When it is necessary to change the position of the vacuum water pump 61, the winch 41 is opened. The movement of the winch 41 drives the steel cable 42 to operate, and the steel cable 42 drives the vacuum water pump 61 to move inside the pumping well 3. When the vacuum pump 61 is in the appropriate position, the winch 41 self-locks to fix the position of the steel cable 42 and the vacuum pump 61. During the movement of the steel cable 42, the steel cable 42 slides inside the elastic rubber pad 43 and the sealing ring 44, thereby ensuring the sealing of the well cover 31 and preventing impurities from entering the interior of the pumping well 3.

[0047] The extraction mechanism 6 draws groundwater into the groundwater purifier 2 for treatment. The extraction mechanism 6 includes a vacuum pump 61, which is connected to the transmission mechanism 4. One end of the vacuum pump 61 is equipped with a drainage hose 62 and a first pumping pipe 63. A second pumping pipe 64 is vertically fixed to the side wall of the first pumping pipe 63. Solenoid valves 66 are installed on the side walls of both the first pumping pipe 63 and the second pumping pipe 64. When the vacuum pump 61 is operating, it generates suction inside the pumping pipe. By controlling the solenoid valve 66, the first pumping pipe 63 or the second pumping pipe 64 is opened respectively, allowing groundwater to enter the drainage hose 62 through the first pumping pipe 63, and allowing LNAPL pollutants and VOC gases to enter the drainage hose 62 through the second pumping pipe 64.

[0048] The first water-suction pipe 63 is internally fixedly connected to a first connecting rod 610. The first connecting rod 610 is internally slidably connected to a fixing block 611 and a second connecting rod 614. The two ends of the first spring 612 are respectively fixedly connected to the fixing block 611 and the first connecting rod 610. The fixing block 611 is internally rotatably connected to the second connecting rod 614. One end of the second connecting rod 614 is fitted with a hemispherical mounting block 68, and the side wall of the second connecting rod 614 is fitted with a funnel-shaped rubber sleeve 613. The side wall of the first water-suction pipe 63 is rotatably connected to a mounting ring 69. Multiple elastic rods 67 are fixedly connected to the side walls of the mounting ring 69 and the mounting block 68, and a geotextile layer 65 is fitted onto the surface of the elastic rods 67. When groundwater is discharged through the first pumping pipe 63, suction is generated inside the first pumping pipe 63 and inside the geotextile layer 65. Groundwater inside the pumping well 3 penetrates the geotextile layer 65 and enters the interior of the first pumping pipe 63. Impurities in the groundwater are blocked by the geotextile layer 65, preventing impurities from entering the vacuum pump 61 and clogging it. When the water inside the geotextile layer 65 moves towards the first... When the water pipe 63 moves in the direction of the water pump, some water enters the interior of the rubber sleeve 613, causing the elastic rubber sleeve 613 to expand and increase the contact area between the rubber sleeve 613 and the water. The thrust of the water on the rubber sleeve 613 increases, causing the rubber sleeve 612 to drive the second connecting rod 614 into the interior of the first connecting rod 610, compressing the first spring 612. At the same time, the second connecting rod 614 drives the mounting block 68 to move towards the first water pump 63, and the mounting block 68 squeezes the elastic rod 67, increasing the degree of bending of the elastic rod 67. The elastic rod 67 pushes the geotextile layer 65 outward to expand, increasing the contact area between the geotextile layer 65 and water, and accelerating the water filtration efficiency of the geotextile layer 65. At the same time, the first spring 612 continuously pushes the second connecting rod 614 outward. As the suction force inside the first pumping pipe 63 changes, the thrust on the rubber pad 613 changes accordingly, thereby driving the second connecting rod 614 and the elastic rod 67 to move back and forth slightly, causing the surface of the geotextile layer 65 to vibrate slightly, reducing the probability of the geotextile layer 65 being blocked.

[0049] A backflushing mechanism 8 for flushing the geotextile layer 65 is symmetrically installed on the side wall of the first pumping pipe 63. The backflushing mechanism 8 includes a backflushing pipe 81, which is funnel-shaped at one end of the side wall of the first pumping pipe 63. The backflushing pipe 81 is fixedly connected to a crossbar 84 and a sealing block 86. The sealing block 86, which is hollow frustum-shaped, is slidably connected to a retaining ball 85. The two ends of the second spring 83 are fixedly connected to the crossbar 84 and the retaining ball 85, respectively. A stop block 82 with an arc-shaped side wall is installed at the connection between the backflushing pipe 81 and the first pumping pipe 63. As the vacuum pump 61 moves up and down, groundwater enters one of the backflush pipes 81. The groundwater causes the retaining ball 85 to move, compressing the second spring 83. The retaining ball 85 separates from the sealing block 86. The groundwater then slides through the backflush pipe 81 across the side wall of the baffle 82 and enters the geotextile layer 65. The side wall of the baffle 82 is arc-shaped, and the outlet of the baffle 82 faces the interior of the geotextile layer 65, allowing the water to be accelerated by the side wall of the baffle 82 before entering the interior of the geotextile layer 65. During the pumping process of the first pumping pipe 63, the baffle block 82 separates the backflushing pipe 81 from the first pumping pipe 63, preventing the backflushing pipe 81 from being opened by internal suction. As water gradually enters the geotextile layer 65 and gradually flows outward, it backflushes the geotextile layer 65, removing impurities adsorbed inside and clearing the air from the geotextile layer 65. Furthermore, the elastic rod 67 is inclined between the mounting ring 69 and the mounting block 68, and adjacent geotextile layers 65... The geotextile layer 65 is arc-shaped. When the geotextile layer 65 moves up and down, the groundwater squeezes the inclined elastic rod 67, thereby pushing the elastic rod 67, the geotextile layer 65, the mounting block 68 and the second connecting rod 614 to rotate in the groundwater, reducing the resistance of the geotextile layer 65 in the water. As the geotextile layer 65 rotates, the groundwater slides over the side wall of the geotextile layer 65, reducing the resistance of water seeping out of the geotextile layer 65, thereby improving the backwash effect of the geotextile layer 65.

[0050] A water pipe 21 is installed inside the manhole cover 31. A drainage hose 62 is installed at the bottom end of the water pipe 21. The top end of the water pipe 21 is connected to the groundwater purifier 2. A flow sensor is installed at the connection between the water pipe 21 and the drainage hose 62. This allows groundwater, LNAPL pollutants, and VOC gases to enter the groundwater purifier 2 through the drainage hose 62 and the water pipe 21, so that the groundwater purifier 2 can purify the groundwater.

[0051] The industrial control computer 1 is internally equipped with a data receiving module, which is electrically connected to a VOC gas sensor 53, a liquid level sensor 55, a density meter 56, a flow sensor, a VOCs turbidity sensor, a dissolved oxygen sensor, a temperature sensor, a pH sensor, a conductivity sensor, and a distance sensor 45. These sensors detect information in the groundwater and upload it to the industrial control computer 1 via an information termination module. The industrial control computer 1 then obtains information on VOCs concentration, water turbidity, dissolved oxygen, temperature, pH, turbidity, conductivity, and other indicators to determine the degree of groundwater pollution. Furthermore, the industrial control computer 1 is electrically connected to a winch 41, a vacuum pump 61, and a solenoid valve 66 to facilitate control of their operation.

[0052] A method for remediating contaminated groundwater in low-permeability formations includes the following steps.

[0053] Step 1: Connect the device to an external power source. The float 51 floats on the water surface. The level sensor 55 and density meter 56 are always positioned at the water surface and inside the liquid to monitor the water level and density. The VOC gas sensor 53 is positioned above the water surface to monitor the volatile organic compound content inside the pumping well 3. The float 73 is positioned in the water and pulls the fence 72 vertically upwards, so that the fence 72 and the mounting cylinder 71 are vertically positioned in the water. Water from inside the pumping well 3 passes through the fence 72 and enters the interior of the mounting cylinder 71. The surface of the mounting cylinder 71 has multiple through holes to facilitate the movement of groundwater inside the mounting cylinder 71, allowing the water inside the mounting cylinder 71 to flow freely. Sensor group 77 comes into contact with water to monitor indicators such as VOCs concentration, turbidity, dissolved oxygen, temperature, pH, conductivity, etc., in groundwater, thereby monitoring the degree of groundwater pollution. The VOCs concentration, turbidity, dissolved oxygen, temperature, pH, turbidity, conductivity, and liquid level density detected by multiple sensors are uploaded to the industrial control computer 1 via an information termination module to complete groundwater monitoring. Real-time logical judgments are made on the groundwater extraction and transmission mechanisms. The information storage module inside the industrial control computer 1 stores various information for easy access, and the information judgment module inside the industrial control computer 1 processes the information to determine the real-time pollution concentration of the groundwater, denoted as C. t The real-time groundwater level inside the pumping well 3 is recorded as H. t The VOC gas content inside the pumping well 3 is denoted as V. tThe sensor group 77 contains a densitometer 56, which monitors the density of the water at the bottom of the pumping well 3 and records it as the bottom density. A densitometer 56 is also installed on the surface of the float 51 to monitor the density of the liquid at the top of the pumping well 3 and records it as the surface density. The information judgment module processes the groundwater density information, and the difference between the bottom density and the surface density is recorded as ρ. t ;

[0054] Step Two: The industrial control computer 1 is equipped with an extraction parameter setting module. This module sets parameter thresholds and, through it, sets a groundwater remediation target value, denoted as C0, within the industrial control computer 1. The highest groundwater level restored within the pumping well 3 is denoted as H0. This highest restored groundwater level should be lower than the static water level within the pumping well 3. The maximum VOC gas content within the pumping well 3 is denoted as V0, and the maximum difference between the bottom density and the surface density is denoted as ρ0. The information judgment module within the industrial control computer 1 continues to operate and judge the information. When C... t <C0, V t <V0, ρ t <ρ0, at this time each sensor is in monitoring state for groundwater; when C t >C0, H t <H0, at this time all sensors remain in monitoring mode for groundwater; when C t >C0, H t>H0, the industrial control computer 1 operates to open the solenoid valve 66 on the side wall of the vacuum water pump 61 and the first water pumping pipe 63. The vacuum water pump 61 pumps groundwater through the first water pumping pipe 63, the drainage hose 62, and the water pipe 21 into the groundwater purifier for treatment. The flow sensor monitors the flow rate and velocity of the groundwater inside the water pipe 21 and uploads the information to the industrial control computer 1. During the pumping process, suction is generated inside the first water pumping pipe 63 and the geotextile layer 65. Groundwater inside the pumping well 3 penetrates the geotextile layer 65 and enters the first water pumping pipe 63. Impurities in the groundwater are blocked by the geotextile layer 65, preventing them from entering the vacuum water pump 61 and clogging it. When the water inside the geotextile layer 65 moves towards the first water pumping pipe 63, some water enters the rubber sleeve 613, causing the elastic rubber sleeve 613 to expand and increase the contact area between the rubber sleeve 613 and the water. The increased thrust of water on the rubber sleeve 613 causes the rubber sleeve 612 to drive the second connecting rod 614 into the first connecting rod 610, compressing the first spring 612. Simultaneously, the second connecting rod 614 drives the mounting block 68 towards the first pumping pipe 63. The mounting block 68 compresses the elastic rod 67, increasing its bending degree. The elastic rod 67 pushes the geotextile layer 65 outward, increasing its contact area with water and accelerating its water filtration efficiency. At the same time, the first spring 612 continuously pushes the second connecting rod 614 outward. As the suction force inside the first pumping pipe 63 changes, the thrust on the rubber pad 613 changes accordingly, causing the second connecting rod 614 and the elastic rod 67 to move back and forth slightly, resulting in continuous slight vibration of the geotextile layer 65 surface, reducing the probability of blockage. When H... t When the water level is less than one-third of H0, the industrial control computer 1 shuts down the vacuum water pump 61 and the solenoid valve 66 to quickly pump the water out of the pumping well 3, keeping the water level inside the pumping well 3 at a low level, which facilitates the seepage of groundwater into the pumping well 3. When not in use, the vacuum water pump 61 does not run, reducing power consumption and saving costs.

[0055] Step 3: When ρ t >ρ0, according to H t The industrial control computer 1 operates and opens the winch 41. The winch 41 moves, driving the steel cable 42. The steel cable 42 drives the vacuum water pump 61 to move inside the pumping well 3. Based on the distance sensor 45, the industrial control computer 1 determines the rising distance of the vacuum water pump 61. When H... tWhen the distance between the lifting distance of the vacuum water pump 61 and the lifting distance of the vacuum water pump 61 is 1.2 meters, the industrial control computer 1 operates to shut down the winch 41. The winch 41 self-locks and fixes the positions of the steel cable 42 and the vacuum pump 61. The second water pumping pipe 64 is vertically installed at one end of the vacuum water pump 61, and the height of the second water pumping pipe 64 is much greater than the height of the vacuum water pump 61, which facilitates the second water pumping pipe 64 entering the LNAPL contaminant layer. The vacuum water pump 61 is still located inside the groundwater (as shown in the attached diagram). Figure 8 (As shown); the industrial control computer 1 operates to open the solenoid valve 66 on the side wall of the vacuum water pump 61 and the second water suction pipe 64, thereby removing the LNAPL contaminants. During the removal process, the industrial control computer 1 operates to make H t The distance between the vacuum water pump 61 and the rising distance of the vacuum water pump 61 is not less than 80 cm, so that the inlet of the second water pumping pipe 64 is below the liquid surface; when ρ t <ρ0, the industrial control computer 1 operates, causing the vacuum water pump 61 to reset and enter the bottom of the well;

[0056] Step 4: As the vacuum water pump 61 rapidly removes the water from inside the pumping well 3, maintaining a low water level inside the well 3, the inner wall of the pumping well 3 and the surrounding soil are exposed. The VOCs adsorbed by the soil on the inner wall of the pumping well 3 and the surrounding soil are released into the interior of the pumping well 3, thus reducing the VOC concentration. t Increase; when V t >V0, according to H t The industrial control computer 1 operates and opens the winch 41. The winch 41 moves, driving the steel cable 42. The steel cable 42 drives the vacuum water pump 61 to move inside the pumping well 3. Based on the distance sensor 45, the industrial control computer 1 determines the rising distance of the vacuum water pump 61. When H... t When the distance between the second water pipe 64 and the rising distance of the vacuum water pump 61 is 0.5 meters, the inlet of the second water pump 64 is located on the water surface (as shown in the attached diagram). Figure 9 As shown), the winch 41 self-locks and fixes the vacuum water pump 61; the industrial control computer 1 operates to open the solenoid valve 66 on the side wall of the vacuum water pump 61 and the second water pumping pipe 64, thereby removing VOC gas, reducing the VOC content in the soil, realizing a combination of liquid phase and gas phase extraction, achieving multiphase extraction, and achieving the purpose of strengthening the synergistic remediation of soil and groundwater; and after the gas inside the pumping well 3 is removed, the internal pressure of the pumping well 3 decreases, causing VOCs in the groundwater and soil to quickly converge into the interior of the pumping well 3, thereby accelerating the efficiency of extracting groundwater and VOCs; when V t <V0, the industrial control computer 1 operates, causing the vacuum water pump 61 to reset and enter the bottom of the well;

[0057] Step 5: As the vacuum water pump 61 moves up and down inside the pumping well 3, the backflush pipe 81 also moves up and down, allowing groundwater to enter one of the backflush pipes 81. The groundwater drives the retaining ball 85 to move, compressing the second spring 83. The retaining ball 85 separates from the sealing block 86, and the groundwater slides through the backflush pipe 81 across the side wall of the baffle 82 into the geotextile layer 65. The side wall of the baffle 82 is arc-shaped, and the outlet of the baffle 82 faces the interior of the geotextile layer 65, allowing the water to be accelerated through the side wall of the baffle 82 before entering the interior of the geotextile layer 65. During the pumping process of the first pumping pipe 63, the baffle block 82 separates the backflushing pipe 81 from the first pumping pipe 63, preventing the backflushing pipe 81 from being opened by internal suction. As water gradually enters the geotextile layer 65 and gradually flows outward, it backflushes the geotextile layer 65, removing impurities adsorbed inside and clearing the air from the geotextile layer 65. Furthermore, the elastic rod 67 is inclined between the mounting ring 69 and the mounting block 68, and the adjacent geotextile layers 65 are arc-shaped. When the geotextile layers 65 move up and down... During the process, groundwater compresses the inclined elastic rod 67, thereby pushing the elastic rod 67, the geotextile layer 65, the mounting block 68, and the second connecting rod 614 to rotate in the groundwater. This reduces the resistance of the geotextile layer 65 to movement in the water. As the geotextile layer 65 rotates, groundwater slides over its sidewalls, reducing the resistance to water seeping outward from the geotextile layer 65. This improves the backwashing effect of the geotextile layer 65, prevents it from clogging, increases its filtration efficiency, and accelerates the pumping rate of the vacuum pump 61 inside the pumping well 3. Furthermore, when the vacuum water pump 61 moves up and down in the water, the float 73 and the vacuum water pump 61 drive the fence 72 to move up and down in the water. During this process, groundwater rushes into the interior of the mounting cylinder 71 through the fence 72, which has an internal funnel-shaped structure. As the groundwater moves inside the fence 72, the space for movement gradually decreases, thereby increasing the flow velocity of the water inside the fence 72 and the mounting cylinder 71. This allows the groundwater to flow quickly over the surface of the sensor group 77, thereby washing away impurities that have settled on the surface of the sensor group 77, improving the sensitivity of the sensor group 77, and facilitating accurate monitoring of various indicators in the groundwater.

[0058] Example 1: Under the conditions that the aquifer is buried at a depth of 2 to 6 m, the aquifer is mainly composed of silty clay-silt, and the permeability coefficient is 0.03 to 0.17 m / d, this device is used to treat groundwater, compared with the traditional continuous extraction method.

[0059] The groundwater extraction rate of the two extraction methods was investigated within 2.5 hours, as shown in the attached instruction manual. Figure 11 As shown, it is determined that by using this device, the amount of groundwater extracted in the same time period is approximately 1.3 times that of traditional continuous pumping.

[0060] The total amount of groundwater pollutants extracted by the two extraction methods within the same time period (2.5 h) was investigated, as shown in the appendix to the instruction manual. Figure 12 As shown, it is determined that by using this device, the amount of groundwater pollutants extracted in the same time period is approximately 1.7 times that of traditional pumping.

[0061] The study investigated the groundwater level variation trends of two extraction methods over the same time period (2.5 h). (See attached instruction manual.) Figure 13 As shown, under the above two working conditions, it is preliminarily determined that the fully intelligent pumping system of the present invention can achieve the following results: the lowest groundwater level is 1.2m within the same time period. When the liquid level drops, polluting gases are released from the exposed soil. For continuous pumping, the liquid level remains high, and most of the soil around the underground well is submerged in water. Pollutants in the soil enter the underground well with the groundwater. However, for intermittent pumping using this device, the groundwater level changes continuously and is low, causing pollutants in the exposed soil to be released. Then, the gaseous pollutants are extracted, accelerating the pollutant removal efficiency.

[0062] As can be seen from the above, the pumping efficiency and the amount of groundwater pollutants extracted are greatly improved after using this device, which accelerates the treatment efficiency of groundwater. Moreover, by combining liquid phase and gas phase extraction, multiphase extraction is achieved, thereby enhancing the synergistic remediation of soil and groundwater.

[0063] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A device for remediating contaminated groundwater in low-permeability formations, characterized in that, include: An industrial control computer (1) controls the working status of the extraction mechanism (6) based on information inside the pumping well (3). A first monitoring mechanism (5) and a second monitoring mechanism (7) monitor the concentration changes of groundwater pollutants and feed back the groundwater pollution status to the industrial control computer (1). The extraction mechanism (6) pumps groundwater into the groundwater purifier (2) for treatment. A transmission mechanism (4) changes the position of the extraction mechanism (6) according to the distribution of groundwater pollutants. The extraction mechanism (6) includes a vacuum water pump (61), which is connected to the transmission mechanism (4). A drain hose (62) and a first water pump (63) are installed at one end of the vacuum water pump (61). A second water pump (64) is vertically fixed to the side wall of the first water pump (63), and a solenoid valve (66) is installed on the side wall of both the first water pump (63) and the second water pump (64). The first pumping pipe (63) is internally fixedly connected to a first connecting rod (610), and the first connecting rod (610) is internally slidably connected to a fixing block (611) and a second connecting rod (614). The two ends of the first spring (612) are respectively fixedly connected to the fixing block (611) and the first connecting rod (610). The second connecting rod (614) is internally rotatably connected to the fixing block (611). A hemispherical mounting block (68) is installed at one end of the second connecting rod (614), and a funnel-shaped rubber sleeve (613) is installed on the side wall of the second connecting rod (614). The side wall of the first pumping pipe (63) is rotatably connected to a mounting ring (69). Multiple elastic rods (67) are fixedly connected to the side walls of the mounting ring (69) and the mounting block (68). A geotextile layer (65) is fitted on the surface of the elastic rod (67). A backflushing mechanism (8) for flushing the geotextile layer (65) is symmetrically installed on the side wall of the first pumping pipe (63). The backflushing mechanism (8) includes a backflushing pipe (81). The backflushing pipe (81) is symmetrically funnel-shaped at one end of the side wall of the first pumping pipe (63). The backflushing pipe (81) is fixedly connected to a crossbar (84) and a sealing block (86). The sealing block (86), which is hollow frustum-shaped inside, is slidably connected to a ball (85). The two ends of the second spring (83) are fixedly connected to the crossbar (84) and the ball (85) respectively. A stop block (82) with an arc-shaped side wall is installed at the connection between the backflushing pipe (81) and the first pumping pipe (63). The outlet of the stop block (82) faces the inside of the geotextile layer (65).

2. The low-permeability groundwater remediation device according to claim 1, characterized in that, The transmission mechanism (4) includes a steel cable (42), one end of which is tied to the side wall of the vacuum pump (61), and the other end of which is wound around the surface of the winch (41). A distance sensor (45) is installed on the side wall of the vacuum pump (61). A well cover (31) is installed on the surface of the pumping well (3), and the winch (41) is placed on the surface of the well cover (31). A rubber pad (43) is installed inside the well cover (31), and multiple sealing rings (44) are installed equidistantly inside the rubber pad (43). The steel cable (42) is slidably connected to the inside of the rubber pad (43) and the sealing rings (44).

3. The low-permeability groundwater remediation device according to claim 2, characterized in that, The first monitoring mechanism (5) includes a float (51) that floats on the surface of groundwater inside the pumping well (3). A mounting plate (54) is installed on the bottom surface of the float (51), and a liquid level sensor (55) and a density meter (56) are installed on the surface of the mounting plate (54). A support rod (52) is fixedly connected at the center of the mounting plate (54) and the float (51), and a VOC gas sensor (53) is installed at the top of the support rod (52). A sliding sleeve (58) is slidably connected to the side wall of the steel cable (42), and the two ends of the sliding rod (57) are obliquely fixedly connected to the sliding sleeve (58) and the mounting plate (54).

4. The low-permeability groundwater remediation device according to claim 3, characterized in that, The second monitoring mechanism (7) includes an installation cylinder (71), with fences (72) installed at both ends of the installation cylinder (71). One of the fences (72) is connected to a float (73) by multiple ropes (74), and a fixing rope (75) is installed on the side wall of the other fence (72). One end of the fixing rope (75) is fixedly connected to the vacuum water pump (61), and a fixed pulley (76) is installed on the side wall of the vacuum water pump (61), and the side wall of the fixed pulley (76) is slidably connected to the fixing rope (75).

5. The low-permeability groundwater remediation device according to claim 4, characterized in that, The sidewall of the fence (72) is arc-shaped, and the interior of the fence (72) has a funnel-shaped structure. The inner diameter of the connection between the fence (72) and the mounting cylinder (71) is the smallest.

6. The low-permeability groundwater remediation device according to claim 5, characterized in that, The sensor group (77) is installed inside the mounting cylinder (71), and the sensor group (77) includes a densitometer (56), a VOCs turbidity sensor, a dissolved oxygen sensor, a temperature sensor, a pH sensor, and a conductivity sensor.

7. The low-permeability groundwater remediation device according to claim 6, characterized in that, A water pipe (21) is installed inside the manhole cover (31). A drainage hose (62) is installed at the bottom end of the water pipe (21). The top end of the water pipe (21) is connected to the underground water purifier (2). A flow sensor is installed at the connection between the water pipe (21) and the drainage hose (62).

8. The low-permeability groundwater remediation device according to claim 7, characterized in that, The industrial control computer (1) is equipped with a data receiving module. The data receiving module is electrically connected to the VOC gas sensor (53), liquid level sensor (55), density meter (56), flow sensor, VOCs turbidity sensor, dissolved oxygen sensor, temperature sensor, pH sensor, conductivity sensor and distance sensor (45). The industrial control computer (1) is also electrically connected to the winch (41), vacuum water pump (61) and solenoid valve (66).

9. A method for remediating contaminated groundwater in low-permeability formations, using the low-permeability groundwater remediation device described in claim 8, the method comprising the following steps: Step 1: Connect the device to an external power source. The first monitoring mechanism (5) operates to monitor the water level, water density, and volatile organic compound (VOC) content inside the pumping well (3). The second monitoring mechanism (7) monitors the VOC concentration, turbidity, dissolved oxygen, temperature, pH, conductivity, and density in the groundwater. The monitored information is uploaded to the industrial control computer (1). The information judgment module inside the industrial control computer (1) processes the information and determines the real-time pollution concentration of the groundwater, denoted as C. t The real-time groundwater level inside the pumping well (3) is denoted as H. t The VOC gas content inside the pumping well (3) is denoted as V. t The difference between the bottom density and the surface density of the water in the pumping well (3) is denoted as ρ. t ; Step 2: The industrial control computer (1) is equipped with an extraction parameter setting module. The extraction parameter setting module sets the groundwater remediation target value, denoted as C0, and the highest groundwater level restored in the pumping well (3), denoted as H0. The highest groundwater level restored should be less than the static water level in the pumping well (3). The maximum VOC gas content in the pumping well (3) is denoted as V0, and the maximum difference between the bottom density and the surface density is denoted as ρ0. The information judgment module inside the industrial control computer (1) continues to operate to judge the information. When C t <C0, V t <V0, ρ t <ρ0, at this time each sensor is in monitoring state for groundwater; when C t >C0, H t <H0, at this time all sensors remain in monitoring mode for groundwater; when C t >C0, H t >H0, the industrial control computer (1) operates to open the extraction mechanism (6), quickly pumping away the water inside the pumping well (3), keeping the water level inside the pumping well (3) low, making it easy for groundwater to seep into the pumping well (3), and when not in use, the extraction mechanism (6) does not operate, reducing power consumption and saving costs; Step 3: When ρ t >ρ0, according to H t The industrial control computer (1) operates to open the transmission mechanism (4), driving the extraction mechanism (6) to move upward inside the pumping well (3). When H t When the distance between the extraction mechanism (6) and the rising distance of the extraction mechanism (6) is 1.2 meters, the position of the extraction mechanism (6) is fixed, and the extraction mechanism (6) operates to remove LNAPL contaminants; when ρ t <ρ0, the industrial control computer (1) operates, causing the extraction mechanism (6) to reset; Step 4: When V t >V0, according to H t The industrial control computer (1) operates to open the transmission mechanism (4), driving the extraction mechanism (6) to move upward inside the pumping well (3). When H t When the distance between the extraction mechanism (6) and the rising distance is 0.5 meters, the extraction mechanism (6) is opened to extract VOC gas, reduce the VOC content in the soil, realize the combination of liquid phase and gas phase extraction, realize multiphase extraction, and achieve the purpose of strengthening the synergistic remediation of soil and groundwater; when V t <V0, the industrial control computer (1) operates, causing the extraction mechanism (6) to reset and enter the bottom of the well; Step 5: During the up-and-down movement of the extraction mechanism (6), water enters the interior of the backflushing mechanism (8), causing the water to enter the interior of the geotextile layer (65) and align with the backflushing, preventing the geotextile layer (65) from becoming blocked and accelerating the pumping rate of the extraction mechanism (6); and when the extraction mechanism (6) moves, it drives the second monitoring mechanism (7) to move up and down, so that the groundwater does not constantly flush the second monitoring mechanism (7), removing the dust on the surface of the second monitoring mechanism (7) and improving the monitoring sensitivity of the second monitoring mechanism (7).

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