Low-permeability stratum polluted underground water remediation device and method

Abstract

The invention provides a low-permeability stratum polluted groundwater remediation device and method.The low-permeability stratum polluted groundwater remediation device comprises an industrial personal computer, the industrial personal computer is used for controlling the working state of an extraction mechanism according to information in a pumping well, and a first monitoring mechanism and a second monitoring mechanism monitor the concentration change of groundwater pollutants and feed the groundwater pollution condition back to the industrial personal computer; the extraction mechanism is used for pumping underground water into the underground water purifier for treatment; the transmission mechanism changes the position of the extraction mechanism according to the distribution of underground water pollutants; the low-permeability stratum polluted groundwater remediation device and method have the advantages that the groundwater extraction efficiency is improved, the groundwater pollutant extraction effect can be effectively improved, and the groundwater extraction operation cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of groundwater remediation, and particularly relates to a low-permeability stratum contaminated groundwater remediation device and method. BACKGROUND

[0002] Groundwater pollution has the characteristics of concealment, long-term and difficulty in recovery, and once high-concentration organic matter enters the groundwater environment, the recovery cost, management cost, ecological cost and its high cost are serious threats to human health and ecological safety. Therefore, it is important to carry out contaminated groundwater risk control and remediation.

[0003] Groundwater extraction treatment is one of the commonly used groundwater risk control and remediation technologies, which can achieve rapid reduction of pollutant concentration by extracting non-aqueous phase liquids (NAPL), dissolved organic pollutants, heavy metals, inorganic salts and other pollutants in groundwater to the ground for treatment. However, in low-permeability strata, continuous extraction treatment often leads to flow interruption, resulting in reduced extraction efficiency, and the adsorption and desorption of soil particles to pollutants also leads to tailing and rebound of pollutant concentration.

[0004] Therefore, it is necessary to provide a new low-permeability stratum contaminated groundwater remediation device and method to solve the above technical problems. SUMMARY

[0005] The technical problem solved by the present application is to provide a low-permeability stratum contaminated groundwater remediation device and method that improves groundwater extraction efficiency, effectively improves groundwater pollutant extraction effect, and reduces groundwater extraction operation cost.

[0006] To solve the above technical problems, the low-permeability stratum contaminated groundwater remediation device provided by the present application comprises: an industrial computer, which is used to control the working state of an extraction mechanism according to the information inside a water extraction well, a first monitoring mechanism and a second monitoring mechanism monitor the concentration change of groundwater pollutants and feed the groundwater pollution condition to the industrial computer, and the extraction mechanism extracts groundwater into the inside of a groundwater purifier for treatment; a transmission mechanism changes the position of the extraction mechanism according to the distribution of groundwater pollutants; The extraction mechanism comprises a vacuum water pump connected to the transmission mechanism, one end of the vacuum water pump is provided with a drainage hose and a first water suction pipe, the side wall of the first water suction pipe is vertically and fixedly connected with a second water suction pipe, and the side wall of the first water suction pipe and the second water suction pipe is provided with an electromagnetic valve; the inside of the first water suction pipe is fixedly connected with a first connecting rod, the inside of the first connecting rod is slidably connected with a fixed block and a second connecting rod, and the two ends of a first spring are fixedly connected with the fixed block and the first connecting rod; the inside of the fixed block is rotatably connected with the second connecting rod, one end of the second connecting rod is provided with a hemispherical mounting block, and the side wall of the second connecting rod is provided with a rubber sleeve with a funnel-shaped inside; the side wall of the first water suction pipe is rotatably connected with a mounting ring, the side wall of the mounting ring and the mounting block is fixedly connected with a plurality of elastic rods, and the surface of the elastic rods is provided with a geotextile layer. The side wall of the first water suction pipe is symmetrically provided with a backflushing mechanism for flushing the geotextile layer, the backflushing mechanism comprises a backflushing pipe, the side wall of the first water suction pipe is symmetrically provided with a funnel-shaped backflushing pipe at one end, the backflushing pipe is fixedly connected with a cross rod and a sealing block, the inside of the sealing block with a hollow circular truncated cone shape is slidably connected with a clamping ball, and the two ends of a second spring are fixedly connected with the cross rod and the clamping ball; the connecting position of the backflushing pipe and the first water suction pipe is provided with a side wall arc-shaped stop block, and the water outlet position of the stop block faces the inside of the geotextile layer.

[0007] Preferably, the transmission mechanism comprises a steel cable, one end of the steel cable is tied to the side wall of the vacuum water pump, the other end of the steel cable is wound on the surface of a winch, and the side wall of the vacuum water pump is provided with a distance sensor; the surface of the water well is provided with a well cover, the winch is arranged on the surface of the well cover; the inside of the well cover is provided with a rubber pad, a plurality of sealing rings are equidistantly arranged in the inside of the rubber pad, and the inside of the rubber pad and the sealing rings is slidably connected with the steel cable.

[0008] Preferably, the first monitoring mechanism comprises a floating plate, the floating plate floats on the surface of underground water in the water well, the bottom surface of the floating plate is provided with a mounting plate, the surface of the mounting plate is provided with a liquid level sensor and a densimeter; the center of the mounting plate and the floating plate is fixedly connected with a support rod, and the top end of the support rod is provided with a VOC gas sensor; the side wall of the steel cable is slidably connected with a sliding sleeve, and the two ends of a sliding rod are obliquely and fixedly connected with the sliding sleeve and the mounting plate.

[0009] Preferably, the second monitoring mechanism comprises a mounting cylinder, both ends of the mounting cylinder are provided with fences, one of the fences is connected with a floating buoy through a plurality of ropes, and the side wall of the other fence is provided with a fixed rope; one end of the fixed rope is fixedly connected with the vacuum water pump, the side wall of the vacuum water pump is provided with a fixed pulley, and the side wall of the fixed pulley is slidably connected with the fixed rope.

[0010] Preferably, the side wall of the fence is arc-shaped, and the inner part of the fence is funnel-shaped, and the inner diameter of the connection part between the fence and the installation cylinder is the smallest.

[0011] Preferably, the inside of the installation cylinder is installed with a sensor group, and the sensor group includes a densimeter, a VOC turbidity sensor, a dissolved oxygen sensor, a temperature sensor, a PH sensor, a conductivity sensor, and other underground water monitoring components.

[0012] Preferably, the inside of the well cover is installed with a water pipe, the bottom end of the water pipe is installed with a drainage hose, the top end of the water pipe is connected with the underground water purifier, and a flow sensor is installed at the connection part between the water pipe and the drainage hose.

[0013] Preferably, the inside of the industrial computer is installed with a data receiving module, the data receiving module is electrically connected between the VOC gas sensor, the liquid level sensor, the densimeter, the flow sensor, the VOC turbidity sensor, the dissolved oxygen sensor, the temperature sensor, the PH sensor, the conductivity sensor, and the distance sensor, and the industrial computer is electrically connected with the winch, the vacuum water pump, and the electromagnetic valve.

[0014] A method for repairing polluted underground water in low-permeability strata, specifically comprising the following steps: Step one: connect an external power supply to the device, the first monitoring mechanism operates to monitor the water level, the density of the water surface, and the VOC content of the water surface in the water well; the second monitoring mechanism monitors the VOC concentration, the water turbidity, the dissolved oxygen, the temperature, the pH, the turbidity, the conductivity, the density, and other indicators of the underground water, and uploads the monitored information to the industrial computer; the information processing module in the industrial computer processes the information to determine the real-time pollution concentration of the underground water, denoted as C t , the real-time water level of the underground water in the water well is denoted as H t , the VOC content in the water well is denoted as V t , and the difference between the density of the water bottom and the density of the water surface is denoted as ρ t ; Step two: the industrial computer is provided with an extraction parameter setting module, which sets the target value of the underground water repair in the industrial computer, denoted as C0, the highest water level of the underground water recovery in the water well, denoted as H0, which should be less than the still water level in the water well; the maximum VOC content in the water well is denoted as V0, and the maximum difference between the density of the water bottom and the density of the water surface is denoted as ρ0; the information processing module in the industrial computer continues to operate to determine the information, and when C t <C0, V t <V0, ρ t<ρ0, at this time, each sensor is in a monitoring state for underground water; when C t >C0, H t <H0, at this time, each sensor is in a monitoring state for underground water; when C t >C0, H t >H0, the industrial computer operates to open the extraction mechanism, quickly extracts water in the well to keep the inside of the well at a low water level, facilitates the infiltration of underground water into the inside of the well, and when not in use, the extraction mechanism does not operate, reducing power consumption and saving costs; Step three: when ρ t >ρ0, according to H t , the industrial computer operates to open the transmission mechanism to drive the extraction mechanism to move upward in the well, when the interval between H t and the rising distance of the extraction mechanism is 1.2 meters, the extraction mechanism is fixed, and the extraction mechanism operates to extract LNAPL pollutants; when ρ t <ρ0, the industrial computer operates to reset the extraction mechanism; Step four: when V t >V0, according to H t , the industrial computer operates to open the transmission mechanism to drive the extraction mechanism to move upward in the well, when the interval between H t and the rising distance of the extraction mechanism is 0.5 meters, the extraction mechanism 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 soil-underground water collaborative repair; when V t <V0, the industrial computer operates to reset the extraction mechanism into the well bottom; Step five: when the extraction mechanism moves up and down, water enters the inside of the backflushing mechanism to align backflushing of the water into the inside of the geotextile layer, avoid the blockage of the geotextile layer, and accelerate the water extraction rate of the extraction mechanism; and the extraction mechanism drives the second monitoring mechanism to move up and down when moving, so that underground water does not fixedly flush the second monitoring mechanism, removes dust on the surface of the second monitoring mechanism, and improves the monitoring sensitivity of the second monitoring mechanism.

[0015] Compared with the related art, the low-permeability stratum contaminated underground water repair device and method provided by the application has the following beneficial effects: The application provides a low-permeability stratum contaminated groundwater remediation device and method. During the process of extracting groundwater, according to the groundwater level, the industrial computer intermittently operates to open the extraction mechanism, quickly extracts the water in the well, keeps the inside of the well at a low water level, facilitates the leakage of groundwater into the inside of the well, and when not in use, the extraction mechanism does not operate, reducing power consumption and saving costs. When the LNAPL on the surface of the groundwater is excessive, the industrial computer operates to open the transmission mechanism, drives the extraction mechanism to move upward in the well, makes the water extraction port of the extraction mechanism enter the LNAPL layer, and makes the extraction mechanism quickly extract the LNAPL on the surface of the water; Because the inside of the well is kept at a low water level for a long time, the inner wall of the well and the soil around it are in an exposed state, the inner wall of the well and the soil around it adsorb VOC released into the inside of the well, increase the VOC content in the gas in the inside of the well, and when the limit value is reached; the industrial computer operates to open the transmission mechanism, drives the extraction mechanism to move upward in the well, makes the water extraction port of the extraction mechanism above the surface of the water, makes the extraction mechanism extract the VOC gas in the inside of the well, reduces the VOC content in the soil, realizes the combination of liquid-phase and gas-phase extraction when extracting pollutants, realizes multiphase extraction, and achieves the purpose of strengthening the soil-groundwater collaborative remediation; and after the gas in the inside of the well is extracted, the internal pressure of the well is reduced, the VOC in the groundwater and the soil quickly gathers into the inside of the well, thereby accelerating the efficiency of extracting groundwater and VOC; when the extraction mechanism moves up and down in the groundwater, water enters the inside of the backflushing mechanism, makes the water enter the inside of the geotextile layer and align backflush, avoids the blockage of the geotextile layer, and accelerates the water extraction rate of the extraction mechanism; and the second monitoring mechanism moves up and down when the extraction mechanism moves, so that the groundwater does not fixedly flush the second monitoring mechanism, removes the dust on the surface of the second monitoring mechanism, and improves the monitoring sensitivity of the second monitoring mechanism. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 A structure diagram of a preferred embodiment of the low-permeability stratum contaminated groundwater remediation device and method provided by the application is shown in the figure; Figure 2 A structure diagram of a preferred embodiment of the low-permeability stratum contaminated groundwater remediation device and method provided by the application is shown in the figure; Figure 1 An enlarged structure diagram of the A structure shown in the figure; Figure 3 An enlarged structure diagram of the B structure shown in the figure; Figure 1 An enlarged structure diagram of the B structure shown in the figure; Figure 4 An enlarged structure diagram of the C structure shown in the figure; Figure 1 An enlarged structure diagram of the C structure shown in the figure; Figure 5 An enlarged structure diagram of the C structure shown in the figure;Figure 4 The internal structure of the geotextile layer is shown in the figure; Figure 6 The internal structure of the geotextile layer is shown in the figure; Figure 4 The internal structure of the geotextile layer is shown in the figure; Figure 7 The internal structure of the geotextile layer is shown in the figure; Figure 4 The internal structure of the geotextile layer is shown in the figure; Figure 8 The internal structure of the geotextile layer is shown in the figure; Figure 9 The internal structure of the geotextile layer is shown in the figure; Figure 10 The internal structure of the geotextile layer is shown in the figure; Figure 11 The internal structure of the geotextile layer is shown in the figure; Figure 12 The internal structure of the geotextile layer is shown in the figure; Figure 13 The internal structure of the geotextile layer is shown in the figure.

[0017] The internal structure of the geotextile layer is shown in the figure. DETAILED DESCRIPTION

[0018] The application will be further described below in conjunction with the drawings and embodiments.

[0019] Please refer to Figures 1-10 , Figure 1A 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. The first monitoring mechanism 5 includes a floating plate 51 floating on the surface of underground water inside the pumping well 3, the bottom surface of the floating plate 51 is installed with an installation plate 54, the surface of the installation plate 54 is installed with a liquid level sensor 55 and a densimeter 56; the installation plate 54 and the floating plate 51 are fixedly connected with a support rod 52 at the center, and the top end of the support rod 52 is installed with a VOC gas sensor 53; the side wall of the steel cable 42 is slidingly connected with a sliding sleeve 58, and both ends of a sliding rod 57 are fixedly connected with the sliding sleeve 58 and the installation plate 54 in an inclined manner; the buoyancy of the floating plate 51 in water is greater than the gravity received by the floating plate 51, so that the floating plate 51 floats on the water surface; the installation plate 54 is fixed on the bottom surface of the floating plate 51, and the support rod 52 penetrates the center of the inside of the floating plate 51; the density of the installation plate 54 and the support rod 52 is greater than the density of water, so as to increase the weight of the floating plate 51 and the stability on the water surface, and avoid the floating plate 51 from swinging in water; and the floating plate 51 moves up and down inside the pumping well 3 along with the water level, the floating plate 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 in a straight state, and the sliding rod 57 is arranged in an inclined manner, so as to facilitate the sliding rod 57 to drive the sliding sleeve 58 to slide on the surface of the steel cable 42, thereby further improving the stability of the floating plate 51 in water, avoiding the floating plate 51 from tilting in water, so that the liquid level sensor 55 and the densimeter 56 are always located at the water surface position, for monitoring the water level height and the density of the water surface, and the VOC gas sensor 53 is located above the water surface, for monitoring the volatile organic content of the gas inside the pumping well 3.

[0020] The second monitoring mechanism 7 comprises a mounting cylinder 71, both ends of which are mounted with fences 72, one of which is connected with a floating cylinder 73 through a plurality of ropes 74, and the side wall of the other fence 72 is mounted with a fixed rope 75; one end of the fixed rope 75 is fixedly connected with the vacuum water pump 61, the side wall of the vacuum water pump 61 is mounted with a fixed pulley 76, and the side wall of the fixed pulley 76 is slidably connected with the fixed rope 75; the inside of the mounting cylinder 71 is mounted with a sensor group 77, and the sensor group 77 comprises a densimeter 56, a VOCS turbidity sensor, a dissolved oxygen sensor, a temperature sensor, a PH sensor, a conductivity sensor and other underground water monitoring components; the buoyancy generated by the floating cylinder 73 in water is always greater than the downward pulling force it receives, so that the floating cylinder 73 pulls the fence 72 and the fixed cylinder 71 upward through the rope 74, the fixed rope 75 fixes the fence 72 and the fixed cylinder 71, the fixed cylinder 71 is located in water and on one side of the vacuum water pump 61, the fixed rope 75 is connected with the fence 72 after turning through the fixed pulley 76, the center of the fixed pulley 76, the fence 72, the fixed cylinder 71 and the floating cylinder 73 is located on the same straight line, so that the floating cylinder 73 pulls the fence 72 vertically upward, and the fence 72 and the mounting cylinder 71 are vertically located in water, the two fences 72 protect the mounting cylinder 71 from contacting other objects, and protect the mounting cylinder 71 and the sensor group 77 inside the mounting cylinder 71; The water inside the pumping well 3 enters the inside of the mounting cylinder 71 through the fence 72, and the surface of the mounting cylinder 71 is provided with a plurality of through holes, so as to facilitate the movement of underground water in the inside of the mounting cylinder 71, so that the sensor group 77 in the inside of the mounting cylinder 71 contacts water, so as to respectively monitor the VOCs concentration, water turbidity, dissolved oxygen, temperature, pH, turbidity, conductivity and other indexes in underground water, so as to monitor the pollution degree of underground water.

[0021] The sensor group 77 inside comprises a densimeter 56, which monitors the density of the water at the bottom end inside the pumping well 3, which is recorded as the water bottom density; the surface of the floating plate 51 is also mounted with a densimeter 56, which is used to monitor the density of the liquid on the top surface inside the pumping well 3, which is recorded as the water surface density; since LNAPL is a kind of oil-based organic pollutant floating on water, the density of LNAPL is less than that of underground water, by comparing the water bottom density with the water surface density, it is judged whether there is LNAPL on the water surface, so as to facilitate the pumping of LNAPL pollutants from underground water.

[0022] The side wall of the fence 72 is arc-shaped, and the inside of the fence 72 is funnel-shaped, and the inner diameter of the connection between the fence 72 and the installation 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. In this process, the groundwater flows into the inside of the installation cylinder 71 through the fence 72 with a funnel-shaped inside. The movement space of the groundwater in the inside of the fence 72 gradually decreases, thereby increasing the flow rate of the water in the inside of the fence 72 and the installation cylinder 71, making the groundwater quickly flow from the surface of the sensor group 77, thereby washing away the impurities deposited on the surface of the sensor group 77, and improving the sensitivity of the sensor group 77.

[0023] 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 water pump 61, and the other end of which is wound on the surface of the winch 41, and the side wall of the vacuum water pump 61 is installed with a distance sensor 45. The well lid 31 is installed on the surface of the water well 3, and the winch 41 is placed on the surface of the well lid 31. A rubber pad 43 is installed in the inside of the well lid 31, a plurality of sealing rings 44 are installed equidistantly in the inside of the rubber pad 43, and the steel cable 42 is slidably connected to the inside of the rubber pad 43 and the sealing rings 44. 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 operation of the steel cable 42, and the steel cable 42 drives the movement of the vacuum water pump 61 in the inside of the water well 3. When the position of the vacuum pump 61 is appropriate, the self-locking of the winch 41 fixes 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 in the inside of the rubber pad 43 and the sealing rings 44 which have elasticity, thereby ensuring the sealing property of the well lid 31 and avoiding impurities from entering the inside of the water well 3.

[0024] The extraction mechanism 6 extracts groundwater into the inside of the groundwater purifier 2 for treatment. The extraction mechanism 6 includes a vacuum water pump 61, the vacuum water pump 61 is connected to the transmission mechanism 4, one end of the vacuum water pump 61 is installed with a drainage hose 62 and a first water suction pipe 63, the side wall of the first water suction pipe 63 is perpendicularly and fixedly connected to a second water suction pipe 64, and the side walls of the first water suction pipe 63 and the second water suction pipe 64 are both installed with electromagnetic valves 66. During the operation of the vacuum water pump 61, the vacuum water pump 61 generates suction in the inside of the water suction pipe. By controlling the electromagnetic valves 66, the first water suction pipe 63 or the second water suction pipe 64 is opened respectively, so that the groundwater enters the inside of the drainage hose 62 through the first water suction pipe 63, and the LNAPL pollutants and VOC gas enter the inside of the drainage hose 62 through the second water suction pipe 64.

[0025] 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 68 and a second connecting rod 614. The two ends of the first spring 612 are respectively fixedly connected to the fixing block 68 and the first connecting rod 610. The fixing block 68 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 flows towards the first pumping well 63, the pressure is increased. When the water pipe 63 moves in the direction of the first water pipe 63, some water enters the interior of the rubber sleeve 613, causing the elastic rubber sleeve 613 to expand and increasing 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 pipe 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.

[0026] The side wall of the first water pumping pipe 63 is symmetrically installed with a back flushing mechanism 8 for flushing the geotextile layer 65, the back flushing mechanism 8 comprises a back flushing pipe 81, the side wall of the first water pumping pipe 63 is symmetrically installed with a funnel-shaped back flushing pipe 81 at one end, the back flushing pipe 81 is fixedly connected with a horizontal rod 84 and a sealing block 86, the inside of the sealing block 86 is in sliding connection with a clamping ball 85, and the two ends of a second spring 83 are fixedly connected with the horizontal rod 84 and the clamping ball 85 respectively; the connection between the back flushing pipe 81 and the first water pumping pipe 63 is installed with a stop block 82 with an arc-shaped side wall; during the up-and-down movement of the vacuum water pump 61, groundwater enters the inside of one of the back flushing pipes 81, the groundwater drives the clamping ball 85 to move and compress the second spring 83, the clamping ball 85 is separated from the sealing block 86, and the groundwater passes through the back flushing pipe 81 and enters the inside of the geotextile layer 65 through the side wall of the stop block 82, the side wall of the stop block 82 is arc-shaped, and the position of the water outlet of the stop block 82 faces the inside of the geotextile layer 65, so that the water enters the inside of the geotextile layer 65 after being accelerated by the side wall of the stop block 82, and during the water pumping process of the first water pumping pipe 63, the stop block 82 separates the back flushing pipe 81 from the first water pumping pipe 63, so as to avoid the suction force generated in the inside of the back flushing pipe 81 from opening the back flushing pipe 81; as the water gradually enters the inside of the geotextile layer 65 and gradually discharges outward, the geotextile layer 65 is back flushed, the impurities adsorbed in the inside of the geotextile layer 65 are removed, and the geotextile layer 65 is dredged; and the elastic rod 67 is obliquely arranged between the mounting ring 69 and the mounting block 68, the geotextile layer 65 between adjacent geotextile layers 65 is arc-shaped, during the up-and-down movement of the geotextile layer 65, the groundwater extrudes the obliquely arranged elastic rod 67, so as to drive the elastic rod 67, the geotextile layer 65, the mounting block 68 and the second connecting rod 614 to rotate in the groundwater, the movement resistance of the geotextile layer 65 in the water is reduced, and as the geotextile layer 65 rotates, the groundwater slides through the side wall of the geotextile layer 65, the resistance of the water in the inside of the geotextile layer 65 to seep outward is reduced, and thus the back flushing effect of the geotextile layer 65 is improved.

[0027] The inside of the well lid 31 is installed with a water pipe 21, the bottom end of the water pipe 21 is installed with a drainage hose 62, the top end of the water pipe 21 is communicated with the groundwater purifier 2, and the connection between the water pipe 21 and the drainage hose 62 is installed with a flow sensor, so as to facilitate the groundwater, LNAPL pollutants and VOC gas to enter the inside of the groundwater purifier 2 through the drainage hose 62 and the water pipe 21, and the groundwater purifier 2 purifies the groundwater.

[0028] The internal installation data acceptance module of the industrial computer 1 is electrically connected with the VOC gas sensor 53, the liquid level sensor 55, the densimeter 56, the flow sensor, the VOCs turbidity sensor, the dissolved oxygen sensor, the temperature sensor, the PH sensor, the conductivity sensor and the distance sensor 45, various sensors detect information in the groundwater, and the information is uploaded to the industrial computer 1 through the information ending module, so that the industrial computer 1 knows the VOCs concentration, water turbidity, dissolved oxygen, temperature, pH, turbidity, conductivity and other indicators, so as to judge the pollution degree of the groundwater, and the industrial computer 1 is electrically connected with the winch 41, the vacuum water pump 61 and the electromagnetic valve 66, so as to facilitate the control of the operation of the winch 41, the vacuum water pump 61 and the electromagnetic valve 66 through the industrial computer 1.

[0029] A method for repairing polluted groundwater in a low-permeability formation, specifically comprising the following steps.

[0030] Step one: connect the power supply to the device, the floating plate 51 floats on the water surface, the liquid level sensor 55 and the densimeter 56 are always located on the water surface and inside the liquid to monitor the water level and the density of the water surface, and the VOC gas sensor 53 is located above the water surface to monitor the volatile organic content in the water well 3; the float 73 is vertically pulled upward in the water to pull the fence 72, so that the fence 72 and the installation cylinder 71 are vertically located in the water, the water in the water well 3 enters the inside of the installation cylinder 71 through the fence 72, and the surface of the installation cylinder 71 is provided with a plurality of through holes to facilitate the movement of groundwater in the installation cylinder 71, so that the sensor group 77 in the installation cylinder 71 is in contact with the water, thereby monitoring the VOCs concentration, water turbidity, dissolved oxygen, temperature, pH, turbidity, conductivity and other indicators in the groundwater, thereby monitoring the pollution degree of the groundwater; the VOCs concentration, water turbidity, dissolved oxygen, temperature, pH, turbidity, conductivity, liquid level density and other indicators of the groundwater detected by the various sensors are uploaded to the industrial computer 1 through the information ending module, the monitoring of the groundwater is completed, real-time logical judgment is made on the groundwater extraction mechanism and the transmission mechanism, and the information storage module in the industrial computer 1 stores various information for people to use, and the information judgment module in the industrial computer 1 processes the information to judge the real-time pollution concentration of the groundwater, recorded as C t , the real-time water level of the groundwater in the water well 3 is recorded as H t , and the VOC gas content in the water well 3 is recorded as V tThe sensor group 77 contains a densimeter 56 inside, which monitors the density of the water at the bottom of the well 3, denoted as the water bottom density; the surface of the floating plate 51 is also equipped with a densimeter 56, which monitors the density of the liquid at the top of the well 3, denoted as the water surface density; the information judgment module processes the groundwater density information, and the difference between the water bottom density and the water surface density is denoted as ρ t ; Step two: the industrial computer 1 is internally provided with an extraction parameter setting module, which sets a parameter threshold value; the extraction parameter setting module sets a groundwater remediation target value in the industrial computer 1, denoted as C0; the highest water level of the groundwater recovery in the well 3 is denoted as H0, which should be less than the static water level in the well 3; the maximum VOC gas content in the well 3 is denoted as V0, and the maximum difference between the water bottom density and the water surface density is denoted as ρ0; the information judgment module in the industrial 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 a monitoring state for the groundwater; when C t >C0、H t <H0, at this time, each sensor remains in a monitoring state for the 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. 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; 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 1 is removed, the internal pressure of the pumping well 1 decreases, causing VOCs in the groundwater and soil to quickly converge into the interior of the pumping well 1, 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; Step five: when the vacuum water pump 61 moves up and down in the well 3, the backflush pipe 81 moves up and down, groundwater enters one of the backflush pipes 81, groundwater drives the ball 85 to move and compress the second spring 83, the ball 85 separates from the sealing block 86, groundwater enters the geotextile layer 65 through the backflush pipe 81, the side wall of the block 82 is arc-shaped, the outlet of the block 82 is towards the inside of the geotextile layer 65, groundwater accelerates in the side wall of the block 82 and enters the geotextile layer 65, the block 82 separates the backflush pipe 81 from the first water pump 63 to avoid the suction in the backflush pipe 81 opening the backflush pipe 81; groundwater gradually enters the geotextile layer 65 and gradually discharges outside, thereby backflushing the geotextile layer 65, removing impurities adsorbed in the geotextile layer 65, and dredging the geotextile layer 65; the elastic rod 67 is inclined between the mounting ring 69 and the mounting block 68, the geotextile layer 65 between adjacent geotextile layers 65 is arc-shaped, when the geotextile layer 65 moves up and down, groundwater extrudes the inclined elastic rod 67, thereby driving the elastic rod 67, the geotextile layer 65, the mounting block 68, and the second connecting rod 614 to rotate in groundwater, reducing the resistance of the geotextile layer 65 in water, and as the geotextile layer 65 rotates, groundwater slides from the side wall of the geotextile layer 65, reducing the resistance of water in the geotextile layer 65 to seep outwards, thereby improving the backflushing effect of the geotextile layer 65, avoiding the geotextile layer 65 from being blocked, improving the filtering efficiency of the geotextile layer 65, and accelerating the pumping rate of the vacuum water pump 61 in the well 3; when the vacuum water pump 61 moves up and down in water, the float 73 and the vacuum water pump 61 drive the fence 72 to move up and down in water, in this process, groundwater flows into the mounting cylinder 71 through the fence 72 with a funnel-shaped structure inside, the movement space of groundwater in the fence 72 gradually decreases, thereby increasing the flow rate of groundwater in the fence 72 and the mounting cylinder 71, making groundwater quickly flow from the surface of the sensor group 77, thereby washing away impurities deposited on the surface of the sensor group 77, improving the sensitivity of the sensor group 77, and facilitating accurate monitoring of various indicators in groundwater.

[0031] Example one: under the condition that the aquifer depth is 2-6 m, the aquifer is mainly silty clay-silt, and the permeability coefficient is 0.03-0.17 m / d, the device is used to treat groundwater, and the traditional continuous extraction is compared. The extraction amounts of groundwater in two extraction methods within 2.5 h are investigated, as shown in the attachedFigure 11 As shown, it is determined that the extraction amount of groundwater is about 1.3 times of that of the traditional continuous pumping in the same time by using the device.

[0032] The total extraction amount of groundwater pollutants in the same time (2.5 h) by the two extraction methods is investigated, and the results are shown in the accompanying drawings of the specification. Figure 12 As shown, it is determined that the extraction amount of groundwater pollutants is about 1.7 times of that of the traditional pumping in the same time by using the device.

[0033] The variation trend of groundwater level in the same time (2.5 h) by the two extraction methods is investigated, and the results are shown in the accompanying drawings of the specification. Figure 13 As shown, it is determined that the lowest point of groundwater level is 1.2 m in the same time by using the full-intelligent pumping system of the application under the above two working conditions, and the pollutants in the exposed soil are released when the liquid level drops; for continuous pumping, the liquid level remains high, and most of the soil around the underground well is located in the water, so that the pollutants in the soil enter the underground well with the groundwater; and for intermittent pumping by using the device, the pollutants in the exposed soil are released due to the continuous change of the groundwater level and the low liquid level, and then the gaseous pollutants are extracted, thereby accelerating the cleaning efficiency of the pollutants.

[0034] As known from the above, the pumping efficiency and the extraction amount of groundwater pollutants are greatly improved by using the device, thereby accelerating the treatment efficiency of the groundwater, and the multi-phase extraction is realized by combining the liquid-phase extraction with the gas-phase extraction, thereby achieving the purpose of strengthening the soil-groundwater collaborative remediation.

[0035] The above description is only an embodiment of the application, and does not limit the patent scope of the application, and any equivalent structure or equivalent flow transformation by using the content of the specification and the drawings, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the application.

Claims

1. A device for remediating groundwater contaminated by a low permeability formation, characterized by, Include: Industrial computer (1), the industrial computer (1) is used for controlling the working state of the extraction mechanism (6) according to the information inside the pumping well (3), the first monitoring mechanism (5) and the second monitoring mechanism (7) monitor the concentration change of groundwater pollutants, and feedback the groundwater pollution condition to the industrial computer (1), the extraction mechanism (6) draws groundwater into the inside of the groundwater purifier (2) for treatment; The 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), the vacuum water pump (61) is connected with the transmission mechanism (4), one end of the vacuum water pump (61) is provided with a drainage hose (62) and a first water pump (63), the side wall of the first water pump (63) is vertically connected with a second water pump (64), and the side wall of the first water pump (63) and the second water pump (64) is provided with an electromagnetic valve (66); The inside of the first water pump (63) is fixedly connected with a first connecting rod (610), the inside of the first connecting rod (610) is slidably connected with a fixed block (68) and a second connecting rod (614), and the two ends of a first spring (612) are fixedly connected with the fixed block (68) and the first connecting rod (610); The inside of the fixed block (68) is rotatably connected with the second connecting rod (614), one end of the second connecting rod (614) is provided with a hemispherical mounting block (68), and the side wall of the second connecting rod (614) is provided with a rubber sleeve (613) with a funnel shape; The side wall of the first water pump (63) is rotatably connected with a mounting ring (69), the side wall of the mounting ring (69) and the mounting block (68) is fixedly connected with a plurality of elastic rods (67), and the surface of the elastic rod (67) is provided with a layer of geotextile layer (65); The side wall of the first water pump (63) is symmetrically provided with a backflushing mechanism (8) for flushing the geotextile layer (65), the backflushing mechanism (8) includes a backflushing pipe (81), the side wall of the first water pump (63) is symmetrically provided with a funnel-shaped backflushing pipe (81), the backflushing pipe (81) is fixedly connected with a cross bar (84) and a sealing block (86), the inside of the sealing block (86) with a hollow circular truncated cone shape is slidably connected with a clamping ball (85), and the two ends of a second spring (83) are fixedly connected with the cross bar (84) and the clamping ball (85); The connecting part of the backflushing pipe (81) and the first water pump (63) is provided with an arc-shaped stop block (82), and the position of the water outlet of the stop block (82) faces the inside of the geotextile layer (65).

2. The low permeability formation contaminated groundwater remediation device of claim 1, wherein, The transmission mechanism (4) includes a steel cable (42), one end of the steel cable (42) is tied to the side wall of the vacuum water pump (61), the other end of the steel cable (42) is wound on the surface of the winch (41), and the side wall of the vacuum water pump (61) is installed with a distance sensor (45); the surface of the well (3) is installed with a well cover (31), and the winch (41) is placed on the surface of the well cover (31); the inside of the well cover (31) is installed with a rubber pad (43), a plurality of sealing rings (44) are installed equidistantly in the inside of the rubber pad (43), and the inside of the rubber pad (43) and the sealing ring (44) are slidably connected with the steel cable (42).

3. The low permeability formation contaminated groundwater remediation device of claim 2, wherein, The first monitoring mechanism (5) includes a floating plate (51) floating on the surface of underground water in the well (3), the bottom surface of the floating plate (51) is installed with a mounting plate (54), the surface of the mounting plate (54) is installed with a liquid level sensor (55) and a densimeter (56); the center of the mounting plate (54) and the floating plate (51) is fixedly connected with a support rod (52), and the top end of the support rod (52) is installed with a VOC gas sensor (53); the side wall of the steel cable (42) is slidably connected with a sliding sleeve (58), and both ends of a sliding rod (57) are fixedly connected with the sliding sleeve (58) and the mounting plate (54).

4. The low permeability formation contaminated groundwater remediation device of claim 3, wherein, The second monitoring mechanism (7) includes a mounting cylinder (71), both ends of the mounting cylinder (71) are installed with fences (72), one of the fences (72) is connected with a floating buoy (73) through a plurality of ropes (74), and the side wall of the other fence (72) is installed with a fixed rope (75); one end of the fixed rope (75) is fixedly connected with the vacuum water pump (61), the side wall of the vacuum water pump (61) is installed with a fixed pulley (76), and the side wall of the fixed pulley (76) is slidably connected with the fixed rope (75).

5. The low permeability formation contaminated groundwater remediation device of claim 4, wherein, The side wall of the fence (72) is arc-shaped, and the inside of the fence (72) is in a funnel-shaped structure, and the inner diameter of the connection between the fence (72) and the mounting cylinder (71) is the smallest.

6. The low permeability formation contaminated groundwater remediation device of claim 5, wherein, The inside of the mounting cylinder (71) is installed with a sensor group (77), and the sensor group (77) includes a densimeter (56), a VOC turbidity sensor, a dissolved oxygen sensor, a temperature sensor, a PH sensor, and a conductivity sensor.

7. The low permeability formation contaminated groundwater remediation device of claim 6, wherein, The inside of the well cover (31) is installed with a water pipe (21), the bottom end of the water pipe (21) is installed with a drainage hose (62), the top end of the water pipe (21) is communicated with the underground water purifier (2), and a flow sensor is installed at the connection between the water pipe (21) and the drainage hose (62).

8. The low permeability formation contaminated groundwater remediation device of claim 7, wherein, The inside of the industrial computer (1) is installed with a data receiving module, which is electrically connected with the VOC gas sensor (53), the liquid level sensor (55), the densimeter (56), the flow sensor, the VOC turbidity sensor, the dissolved oxygen sensor, the temperature sensor, the PH sensor, the conductivity sensor and the distance sensor (45), and the industrial computer (1) is electrically connected with the winch (41), the vacuum water pump (61) and the electromagnetic valve (66).

9. The low permeability formation contaminated groundwater remediation device of claim 8, wherein, The method comprises the following steps. Step one: the device is connected to the power supply, the first monitoring mechanism (5) operation monitoring the water level inside the well (3), the density of the water surface and gas volatile organic content; the second monitoring mechanism (7) monitoring the concentration of VOCs in groundwater, water turbidity, dissolved oxygen, temperature, pH, turbidity, conductivity, density and other indicators, the information after monitoring is uploaded to the industrial computer (1), the information judgment module in the industrial computer (1) processes the information, judges the real-time pollution concentration of groundwater, recorded as C t , the real-time water level of groundwater inside the well (3) is recorded as H t , the VOC gas content inside the well (3) is recorded as V t , the difference between the density of the water bottom and the water surface of the well (1) is recorded as p t ; Step two: the inside of the industrial computer (1) is provided with an extraction parameter setting module, the underground water remediation target value is set in the inside of the industrial computer (1) through the extraction parameter setting module, and is recorded as C0, the highest water level of the underground water recovery in the inside of the extraction well (3) is recorded as H0, the highest water level of the underground water recovery should be less than the static water level in the inside of the extraction well (3); the maximum value of the VOC gas content in the inside of the extraction well (3) is recorded as V0, the maximum difference between the water bottom density and the water surface density is recorded as ρ0; the information judgment module in the inside of the industrial 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 a monitoring state for the underground water; when C t >C0, H t <H0, at this time, each sensor keeps in a monitoring state for the underground water; when C t >C0, H t >H0, the industrial computer (1) operates to open the extraction mechanism (6), the water in the inside of the extraction well (3) is quickly extracted away, the inside of the extraction well (3) is kept at a low water level, the underground water is facilitated to seep into the inside of the extraction well (3), and when not in use, the extraction mechanism (6) does not operate, the power consumption is reduced, and the cost is saved; Step three: when ρ t > ρ0, according to H t , the industrial computer (1) operates to open the transmission mechanism (4), driving the extraction mechanism (6) to move upward inside the pumping well (3), when the interval between H t 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 extract LNAPL pollutants; when ρ t < ρ0, the industrial computer 1 operates to reset the extraction mechanism (6); Step four: when V t > V0, according to H t , the industrial computer (1) operates to open the transmission mechanism (4) to drive the extraction mechanism (6) to move upward in the well (3), when the distance between H t and the rising distance of the extraction mechanism (6) 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 multi-phase extraction, and achieve the purpose of strengthening the soil-groundwater collaborative remediation; when V t V0, the industrial computer (1) operates to reset the extraction mechanism (6) into the well bottom; Step five: when the extraction mechanism (6) moves up and down, water enters the inside of the backflushing mechanism (8), so that the water enters the inside of the geotextile layer (65) and aligns backflushing, avoiding the geotextile layer (65) from being blocked, and accelerating the water extraction rate of the extraction mechanism (6); and the extraction mechanism (6) drives the second monitoring mechanism (7) to move up and down when moving, so that the underground water does not fixedly flush the second monitoring mechanism (7), removes the dust on the surface of the second monitoring mechanism (7), and improves the monitoring sensitivity of the second monitoring mechanism (7).

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