Intelligent multiphase extraction equipment and method for groundwater in low permeability heterogeneous formations

Abstract

The present invention belongs to the field of groundwater treatment in contaminated sites, and discloses an intelligent multiphase extraction device and method for groundwater in low-permeability heterogeneous strata, which can realize automatic control of the extraction device and improve the treatment effect of the contaminated site. The device includes a control system, an extraction well, an auxiliary well, a pressure gauge, an inflatable airbag pump, an air suction airbag pump, a pharmaceutical injection pump, an extraction vacuum pump, and an online monitoring device including a flow meter and a water level meter.

Description

Technical Field

[0001] The present invention relates to the field of groundwater treatment in contaminated sites, and in particular to an intelligent multiphase extraction device and method for groundwater in low-permeability heterogeneous strata. Background Art

[0002] In the treatment of contaminated sites, groundwater multiphase extraction technology is a vacuum extraction method that extracts soil gas and groundwater from underground contaminated areas to the surface and separates them to control and repair organic pollutants in soil and groundwater. However, due to the low permeability of the formation (the permeability coefficient of the formation is K≤10 -5 cm / s), heterogeneity and complexity of pollutants. This technology may encounter the phenomenon that pollutant concentrations are difficult to further reduce, or even rebound, which is the so-called tailing and rebound effect. There are two main reasons for this. One is the low permeability and heterogeneity of the stratum itself; the other is that residual pollutants are not completely removed. In addition, traditional groundwater multiphase extraction facilities mostly rely on manual control, and on-site decisions are mainly based on experience rather than being directly related to the site environmental conditions, lacking intelligence. This has led to low remediation efficiency and a significant increase in time and economic costs, which has seriously restricted the need for precise remediation of contaminated sites. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide an intelligent multiphase extraction device and method for groundwater in low-permeability heterogeneous strata, realize automatic control of the extraction device, and improve the treatment effect of contaminated sites.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] In the first aspect, an intelligent multiphase extraction device for groundwater in a low-permeability heterogeneous formation according to an embodiment of the present invention comprises a control system, an extraction well, an auxiliary well, a pressure gauge, an inflation airbag pump, an air suction airbag pump, a chemical injection pump, an extraction vacuum pump, and an online monitoring device including a flow meter and a water level gauge, wherein the auxiliary well is provided with a chemical injection pipe, a first pump air pipe and a first airbag, the wall of the auxiliary well pipe is a first filter layer, the upper part of the auxiliary well pipe is a first sealing layer, and the top of the auxiliary well pipe is provided with a first sealing cover; one end of the first pump air pipe is located in the first airbag, the air inlet of the first pump air pipe passes through the first sealing cover and is located outside the auxiliary well; the inner cavity of the auxiliary well pipe forms a sealed cavity; the extraction well is provided with an extraction pipe, a second pump air pipe and a second airbag, the extraction well pipe The tube wall is the second filter layer, the upper part of the extraction well tube is the second sealing layer, and the top of the extraction well tube is provided with a second sealing cover; one end of the second pump air pipe is located in the second air bag, and the air outlet of the second pump air pipe passes through the second sealing cover and is located outside the extraction well; the inner cavity of the extraction well tube forms a sealed cavity; the pressure gauge is located outside the extraction well and is used to measure the air pressure in the inner cavity of the extraction well tube; the control system is respectively connected to the inflation air bag pump, the suction air bag pump, the drug injection pump, the extraction vacuum pump and the online monitoring device; the extraction pipe is connected to the inlet of the extraction vacuum pump, and the outlet of the extraction vacuum pump is connected to the inlet of the online monitoring device; the air outlet of the second pump air pipe is connected to the suction air bag pump; the drug injection pipe is connected to the drug injection pump, and the air inlet of the first pump air pipe is connected to the inflation air bag pump.

[0006] As a preferred example, the equipment also includes a multiphase separation device, a waste gas treatment device, a waste gas exhaust pipe and a wastewater treatment device; the inlet of the multiphase separation device is connected to the outlet of the online monitoring device, the liquid outlet of the multiphase separation device is connected to the liquid inlet of the wastewater treatment device, the gas outlet of the multiphase separation device is connected to the gas inlet of the waste gas treatment device, and the gas outlet of the waste gas treatment device is connected to the waste gas exhaust pipe.

[0007] As a preferred example, the length of the drug injection pipe is at least 2 / 3 of the height of the auxiliary well; the length of the first pump air pipe is at least 2 / 3 of the height of the auxiliary well.

[0008] As a preferred example, the inner diameter of the drug injection tube is equal to the inner diameter of the extraction tube.

[0009] As a preferred example, at least three auxiliary wells are arranged circumferentially with one extraction well as the center.

[0010] In a second aspect, a method for intelligent multiphase extraction of groundwater according to an embodiment of the present invention comprises the following steps:

[0011] S1. Arrange extraction wells and auxiliary wells at the contaminated site, where the contaminated site is a low-permeability heterogeneous formation;

[0012] S2, the control system controls the extraction vacuum pump to run for a period of time T0, and the online monitoring device feeds back the online monitoring data obtained within the time range of T0 to the control system in real time; during this process, the drug injection pump, the inflation airbag pump and the suction airbag pump are not running;

[0013] S3. The control system makes on-site controls based on the acquired data to achieve the treatment of underground pollutants.

[0014] As a preferred example, the step S3 specifically includes: if the flow meter in the online monitoring device shows that the flow is zero, and the water level depth shown by the water level meter no longer changes, the control system controls the extraction vacuum pump to stop the extraction operation.

[0015] As a preferred example, the step S3 specifically also includes: after controlling the extraction vacuum pump to stop the extraction operation, the control system simultaneously starts the inflation airbag pump and the suction airbag pump to open up the heterogeneous strata, so that the pollutants flow into the extraction pipe with the groundwater.

[0016] As a preferred example, the step S3 specifically also includes: while the control system controls the inflation airbag pump and the suction airbag pump to turn on, if the pressure gauge shows that the air pressure in the inner cavity of the extraction well pipe shows an upward trend and the water level depth shown by the water level gauge of the online monitoring device shows a downward trend, the control system controls the extraction vacuum pump to turn on again to perform the extraction operation.

[0017] As a preferred example, the step S3 specifically also includes: while controlling the extraction vacuum pump to start again, and the inflation airbag pump and the suction airbag pump to run, if the online monitoring device shows that the site pollution characteristic index is no longer decreasing or the concentration rebounds and rises, the control system controls the drug injection pump to inject the drug until the online monitoring device shows that the site pollution characteristic index reaches the remediation target value, stops the drug injection, and shuts down the extraction vacuum pump, the inflation airbag pump and the suction airbag pump at the same time.

[0018] Compared with the prior art, the intelligent multiphase extraction equipment and method for groundwater in low-permeability heterogeneous strata of the present invention can realize automatic control of the extraction equipment and improve the treatment effect of the contaminated site. The equipment includes a control system, an extraction well, an auxiliary well, a pressure gauge, an inflatable airbag pump, an air suction airbag pump, a reagent injection pump, an extraction vacuum pump, and an online monitoring device containing a flow meter and a water level meter. The equipment realizes intelligent start and stop control of the multiphase extraction equipment through the online monitoring device integrating characteristic indicators online monitoring, and the control system controls the inflatable airbag pump, the air suction airbag pump, the reagent injection pump, and the extraction vacuum pump. This breaks through the limitations of traditional reliance on on-site experience, effectively avoids unnecessary energy waste, and promotes the remediation process to move towards a green, low-carbon and environmentally friendly direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1is a schematic structural diagram of an embodiment of the present invention;

[0020] Figure 2 It is a schematic diagram of the layout of the extraction wells and auxiliary wells in an embodiment of the present invention.

[0021] The figure includes: control system 1, extraction well 2, auxiliary well 3, extraction pipe 4, chemical injection pipe 5, first pump air pipe 6, first air bag 7, first sealing layer 8, first filter layer 9, first sealing cover 10, pressure gauge 11, inflation air bag pump 12, suction air bag pump 13, chemical injection pump 14, extraction vacuum pump 15, online monitoring device 16, multi-phase separation equipment 17, waste gas treatment equipment 18, waste gas exhaust pipe 19, wastewater treatment equipment 20, second pump air pipe 21, second air bag 22, second filter layer 23, second sealing layer 24, second sealing cover 25. DETAILED DESCRIPTION

[0022] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings.

[0023] The technical solution of the present invention is applicable to low permeability heterogeneous formations. Low permeability formations refer to formations with a permeability coefficient K≤10 -5 Heterogeneous formations refer to formations in which the seepage coefficient of each point in the formation varies with the spatial coordinates, and homogeneous formations refer to formations in which each point in the formation has the same seepage coefficient.

[0024] like Figure 1As shown, an intelligent multiphase extraction device for groundwater suitable for low-permeability heterogeneous formations according to an embodiment of the present invention includes a control system 1, an extraction well 2, an auxiliary well 3, a pressure gauge 11, an air-filled airbag pump 12, an air-suction airbag pump 13, a reagent injection pump 14, an extraction vacuum pump 15, and an online monitoring device 16 including a flow meter and a water level meter. Among them, the flow meter is used to detect the flow of water and air extracted by the extraction pipe 4. The water level meter is used to detect the depth of the water level in the extraction pipe 4. The water level depth refers to the distance from the surface to the groundwater level, so a decrease in the water level depth indicates that water has entered the extraction system. Auxiliary well 3 is provided with a reagent injection pipe 5, a first pump air pipe 6 and a first air bag 7. The wall of the auxiliary well 3 well pipe is a first filter layer 9, the upper part of the auxiliary well 3 well pipe is a first sealing layer 8, and the top of the auxiliary well 3 well pipe is provided with a first sealing cover 10; one end of the first pump air pipe 6 is located in the first air bag 7, and the air inlet of the first pump air pipe 6 passes through the first sealing cover 10 and is located outside the auxiliary well 3. The inner cavity of the well pipe of the auxiliary well 3 forms a sealed cavity. Due to the provision of the first sealing layer 8 and the first sealing cover 10, the inner cavity of the well pipe of the auxiliary well 3 forms a sealed cavity relative to the outside. Extraction well 2 is provided with an extraction pipe 4, a second pump air pipe 21 and a second air bag 22. The wall of the well pipe of the extraction well 2 is a second filter layer 23, the upper part of the well pipe of the extraction well 2 is a second sealing layer 24, and the top of the well pipe of the extraction well 2 is provided with a second sealing cover 25. One end of the second pump air pipe 21 is located in the second air bag 22, and the air outlet of the second pump air pipe 21 passes through the second sealing cover 25 and is located outside the extraction well 2; the inner cavity of the well pipe of the extraction well 2 forms a sealed cavity. Due to the provision of the second sealing layer 24 and the second sealing cover 25, the inner cavity of the well pipe of the extraction well 2 forms a sealed cavity relative to the outside. The pressure gauge 11 is located outside the extraction well 2 and is used to measure the air pressure in the inner cavity of the well pipe of the extraction well 2. The control system 1 is connected to the inflation air bag pump 12, the suction air bag pump 13, the drug injection pump 14, the extraction vacuum pump 15 and the online monitoring device 16 respectively. The extraction pipe 4 is connected to the inlet of the extraction vacuum pump 15, and the outlet of the extraction vacuum pump 15 is connected to the inlet of the online monitoring device 16; the air outlet of the second pump air pipe 21 is connected to the suction air bag pump 13. The drug injection pipe 5 is connected to the drug injection pump 14, and the air inlet of the first pump air pipe 6 is connected to the inflation air bag pump 12. The parameters monitored by the online monitoring device 16 are related to the characteristic indicators of the contaminated site, and at least include pH, flow rate, and characteristic indicators.

[0025] In the equipment of the above embodiment, the control system 1 is connected to the inflation airbag pump 12, the suction airbag pump 13, the agent injection pump 14, the extraction vacuum pump 15 and the online monitoring device 16 respectively. The control system 1 controls the inflation airbag pump 12, the suction airbag pump 13, the agent injection pump 14 and the extraction vacuum pump 15 to start or stop working according to the information transmitted by the online monitoring device 16, and realizes the control of the entire equipment on site, reduces human intervention, and improves the treatment effect of the polluted site. When the data transmitted by the online monitoring device 16 shows that there are no pollutants in the material extracted by the extraction tube 4, the control system 1 controls to turn off the extraction vacuum pump 15. After turning off the extraction vacuum pump 15, the control system 1 simultaneously turns on the inflation airbag pump 12 and the suction airbag pump 13, so that the pollutants flow into the extraction tube 4 with the groundwater flow. If the air pressure in the inner cavity of the extraction well 2 shown by the pressure gauge 11 shows an upward trend and the water level gauge of the online monitoring device 16 shows a downward trend, the control system 1 controls the extraction vacuum pump 15 to turn on again to perform the extraction operation. If the online monitoring device 16 shows that the site pollution characteristic index is no longer decreasing or there is a trend of concentration rebound, the control system 1 controls the reagent injection pump 14 to inject the reagent, and the reagent reacts with the site pollutants without generating secondary pollutants, until the online monitoring device 16 shows that the site pollution characteristic index reaches the remediation target value, the injection is stopped, and the extraction vacuum pump 15, the inflation airbag pump 12 and the suction airbag pump 13 are shut down at the same time.

[0026] In the above embodiment, the control system 1 controls the start or stop of the extraction vacuum pump 15, controls the start and stop of the inflation airbag pump 12 and the suction airbag pump 13, and the inflation and suction levels, and controls the start and stop of the drug injection pump 14 and the injection amount according to the real-time data transmitted by the online monitoring device 16.

[0027] To achieve multiphase separation, as a preferred example, the device also includes a multiphase separation device 17, a waste gas treatment device 18, a waste gas exhaust pipe 19 and a wastewater treatment device 20. The inlet of the multiphase separation device 17 is connected to the outlet of the online monitoring device 16, the liquid outlet of the multiphase separation device 17 is connected to the liquid inlet of the wastewater treatment device 20, the gas outlet of the multiphase separation device 17 is connected to the gas inlet of the waste gas treatment device 18, and the gas outlet of the waste gas treatment device 18 is connected to the waste gas exhaust pipe 19. After the mixture extracted from the extraction pipe 4 is detected by the online monitoring device 16, it flows from the online monitoring device 16 into the multiphase separation device 17. The mixture extracted from the extraction pipe 4 contains liquid and gas. Liquid is such as groundwater. Gas is such as volatile organic matter. The mixture is separated into liquid and gas by the multiphase separation device 17. The liquid flows from the liquid outlet into the wastewater treatment device 20 for treatment. The gas flows from the gas outlet into the waste gas treatment device 18 for treatment, and finally discharged from the waste gas exhaust pipe 19.

[0028] As a preferred example, the length of the reagent injection pipe 5 is at least 2 / 3 of the height of the auxiliary well 3; the length of the first pump air pipe 6 is at least 2 / 3 of the height of the auxiliary well 3. This allows the reagent in the reagent pipe and the pump air in the pump air pipe to fully contact the formation.

[0029] As a preferred example, the inner diameter of the drug injection tube 5 is equal to the inner diameter of the extraction tube 4. This can ensure the consistency of fluid flow, reduce the change in fluid velocity caused by the change in tube diameter, thereby reducing the risk of blockage and improving the extraction efficiency. Preferably, the inner diameter of the pump air tube 6 is 30 mm.

[0030] As a preferred example, Figure 2 As shown, with one extraction well 2 as the center, at least three auxiliary wells 3 are arranged along the circumference. This arrangement can process more pollutants around one extraction well 2 and maximize utilization.

[0031] The embodiment of the present invention also provides a method for intelligent multiphase extraction of groundwater using the above-mentioned device, comprising the following steps:

[0032] S1. Arrange extraction well 2 and auxiliary well 3 in the contaminated site. The contaminated site is a low permeability heterogeneous stratum. The extraction well 2 and auxiliary well 3 can be arranged as follows: Figure 2 As shown, with an extraction well 2 as the center, multiple auxiliary wells 3 are arranged along the circumferential direction.

[0033] S2, the control system 1 controls the extraction vacuum pump 15 to run for a period of time T0, and the online monitoring device 16 feeds back the online monitoring data obtained within the time range of T0 to the control system 1 in real time. During this process, the reagent injection pump 14, the inflation airbag pump 12 and the suction airbag pump 13 are not running. The wall of the well pipe of the extraction well 2 is the second filter layer 23. Groundwater flows into the extraction well 2 from the second filter layer 23. Pollutants in the area around the extraction well 2 flow into the extraction well 2 with the groundwater. When the extraction vacuum pump 15 is running, the groundwater flow and airflow containing pollutants in the extraction well 2 are extracted to the online monitoring device 16 through the extraction pipe 4 for detection. The concentration of characteristic pollutants in the online monitoring device 16 shows a downward trend, the flow meter shows the change trend of the water flow and air flow, and the water level meter shows the change trend of the water level depth in the extraction pipe.

[0034] S3, the control system 1 makes on-site control based on the acquired data to achieve the treatment of underground pollutants. The step S3 specifically includes:

[0035] Step S31: If the flow meter in the online monitoring device 16 shows that the flow is zero and the water level depth shown by the water level meter does not change, it means that no pollutants are extracted from the extraction pipe 4. In order to avoid energy consumption and equipment loss, the control system 1 controls the extraction vacuum pump 15 to stop the extraction operation.

[0036] In step S31, no pollutants are extracted from the extraction pipe 4 because the pollutants within the extraction influence range under the heterogeneous formation have been extracted and the remaining residual pollutants cannot be extracted.

[0037] In step S32, after controlling the extraction vacuum pump 15 to stop the extraction operation, the control system 1 simultaneously turns on the inflation airbag pump 12 and the suction airbag pump 13 to open up the heterogeneous strata, so that the pollutants flow into the extraction pipe 4 along with the groundwater.

[0038] Step S32 is set to break through the bottleneck problem of extraction behavior caused by heterogeneous formations. The inflation airbag pump 12 and the suction airbag pump 13 are turned on at the same time. The inflation airbag pump 12 inflates the first airbag 7 through the first pump air pipe 6. Since the inner cavity of the auxiliary well 3 well pipe forms a sealed cavity, the first airbag 7 expands and the inner cavity of the auxiliary well 3 well pipe forms a high pressure. The suction airbag pump 13 inhales air from the second airbag 22 through the second pump air pipe 21. Since the inner cavity of the extraction well 2 well pipe forms a sealed cavity, the second airbag 22 shrinks and the inner cavity of the extraction well 2 well pipe forms a low pressure. Under the pressure difference, the gas in the auxiliary well 3 passes through the first filter layer 9, the heterogeneous formation, and the second filter layer 22 in turn, and flows to the extraction well 2. During the gas flow process, the heterogeneous formation is opened up, allowing pollutants to flow into the extraction pipe 4 with the groundwater flow. Under the inflation effect of the first pump air pipe 6 and the first air bag 7, and the suction effect of the second pump air pipe 21 and the second air bag 22, the groundwater flow generates a pressure difference, thereby expanding the extraction influence range.

[0039] Step S32 breaks through the limitations of heterogeneous formations and uses an airbag pump system through an inflation and suction method. On the one hand, under the condition of enhanced air pressure, it overcomes the problem of inefficient pollution treatment capacity caused by heterogeneous formations and achieves the homogenization of the formation as much as possible. On the other hand, under the premise of opening up the formation, pollutants can enter the extraction well. In heterogeneous formations, groundwater only flows on the dominant flow path, and there is a "dead path" phenomenon. Pollutants cannot flow with the water in the "dead path". Under homogeneous formation conditions, groundwater can flow in all paths.

[0040] In step S33, while the control system 1 controls the inflation airbag pump 12 and the suction airbag pump 13 to start, if the air pressure in the inner cavity of the well pipe of the extraction well 2 shown by the pressure gauge 11 shows an upward trend and the water level depth shown by the water level gauge of the online monitoring device 16 shows a downward trend, the control system 1 controls the extraction vacuum pump 15 to start again to perform the extraction operation.

[0041] In step S33, the air pressure in the extraction well 2 detected by the pressure gauge 11 shows an increase, indicating that gas has entered the extraction well 2 under the pressure difference between the first airbag 7 and the second airbag 22. The water level depth shown by the water level gauge of the online monitoring device 16 shows a downward trend, indicating that groundwater has entered the extraction system. Therefore, when the air pressure in the well pipe cavity of the extraction well 2 shown by the pressure gauge 11 shows an increase and the water level depth shown by the water level gauge of the online monitoring device 16 shows a downward trend, it means that fluid has entered the extraction pipe 4. At this time, the extraction vacuum pump 15 is turned on again to perform the extraction behavior.

[0042] In step S34, while controlling the extraction vacuum pump 15 to start again, and the inflation airbag pump 12 and the suction airbag pump 13 to run, if the online monitoring device 16 shows that the site pollution characteristic index is no longer decreasing or the concentration rebounds and rises, the control system 1 controls the agent injection pump 14 to inject drugs until the online monitoring device 16 shows that the site pollution characteristic index reaches the remediation target value, stops the injection behavior, and shuts down the extraction vacuum pump 15, the inflation airbag pump 12 and the suction airbag pump 13 at the same time.

[0043] In step S34, the online monitoring device 16 shows that the site pollution characteristic index is no longer decreasing or there is a trend of concentration rebound. This means that even if the inflation airbag pump 12 and the suction airbag pump 13 are turned on, there is still the possibility of residual pollution. At this time, the control system 1 controls the reagent injection pump 14 to inject the medicine. The reagent injection pump 14 passes the reagent into the auxiliary well 3 through the reagent injection pipe 5. Since the pressure in the inner cavity of the well pipe of the auxiliary well 3 is higher than the pressure in the inner cavity of the well pipe of the extraction well 2, the reagent flows out from the first filter layer 9 of the auxiliary well 3 and flows to the soil around the auxiliary well 3, reacting with the pollutants in the soil to reduce residual pollutants. When the online monitoring device 16 shows that the site pollution characteristic index reaches the remediation target value, the injection behavior is stopped, and the extraction vacuum pump 15, the inflation airbag pump 12 and the suction airbag pump 13 are shut down at the same time. This indicates that the groundwater pollutants within the control range of the equipment have been completely extracted.

[0044] The device of the above embodiment, by controlling the inflation airbag pump 12 and the suction airbag pump 13 by the control system 1, intelligently adjusts the expansion degree of the first airbag 7 and the second airbag 22, optimizes the dominant flow path of groundwater, overcomes the problem of formation heterogeneity, ensures that soil and groundwater can achieve more sufficient contact with pollutants, and expands the extraction range. The device avoids the tailing and rebound effects caused by low permeability heterogeneous formations.

[0045] The equipment of the above-mentioned embodiment, by integrating the reagent injection equipment and the control system, intelligently controls the injection time and injection amount of the reagent, further ensuring sufficient reaction between the pollutants and the reagent, thereby achieving complete removal of residual pollutants and making the repair effect more thorough.

[0046] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above specific embodiments. The above specific embodiments and the description in the specification are only for further illustrating the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of the present invention to be protected is defined by the claims and their equivalents.

Claims

1. An intelligent multiphase extraction device for groundwater in low permeability heterogeneous formations, characterized in that: The system comprises a control system (1), an extraction well (2), an auxiliary well (3), a pressure gauge (11), an inflation airbag pump (12), an air suction airbag pump (13), a drug injection pump (14), an extraction vacuum pump (15), and an online monitoring device (16) including a flow meter and a water level meter, wherein: The auxiliary well (3) is provided with a medicine injection pipe (5), a first pump air pipe (6) and a first air bag (7); the wall of the auxiliary well (3) well pipe is a first filter layer (9); the upper part of the auxiliary well (3) well pipe is a first sealing layer (8); the top of the auxiliary well (3) well pipe is provided with a first sealing cover (10); one end of the first pump air pipe (6) is located in the first air bag (7); the air inlet of the first pump air pipe (6) passes through the first sealing cover (10) and is located outside the auxiliary well (3); the inner cavity of the well pipe of the auxiliary well (3) forms a sealed cavity; The extraction well (2) is provided with an extraction pipe (4), a second pump air pipe (21) and a second air bag (22); the wall of the extraction well (2) is a second filter layer (23); the upper part of the extraction well (2) is a second sealing layer (24); the top of the extraction well (2) is provided with a second sealing cover (25); one end of the second pump air pipe (21) is located in the second air bag (22); the air outlet of the second pump air pipe (21) passes through the second sealing cover (25) and is located outside the extraction well (2); the inner cavity of the extraction well (2) forms a sealed cavity; the pressure gauge (11) is located outside the extraction well (2) and is used to measure the air pressure in the inner cavity of the extraction well (2); The control system (1) is respectively connected to the inflation airbag pump (12), the suction airbag pump (13), the drug injection pump (14), the extraction vacuum pump (15) and the online monitoring device (16); The extraction tube (4) is connected to the inlet of the extraction vacuum pump (15), and the outlet of the extraction vacuum pump (15) is connected to the inlet of the online monitoring device (16); the outlet of the second pump air pipe (21) is connected to the suction airbag pump (13); The medicine injection tube (5) is connected to the medicine injection pump (14), and the air inlet of the first pump air tube (6) is connected to the inflation airbag pump (12); The device further comprises a multiphase separation device (17), a waste gas treatment device (18), a waste gas exhaust pipe (19) and a waste water treatment device (20); the inlet of the multiphase separation device (17) is connected to the outlet of the online monitoring device (16), the liquid outlet of the multiphase separation device (17) is connected to the liquid inlet of the waste water treatment device (20), the gas outlet of the multiphase separation device (17) is connected to the gas inlet of the waste gas treatment device (18), and the gas outlet of the waste gas treatment device (18) is connected to the waste gas exhaust pipe (19); If the flow meter in the online monitoring device (16) shows that the flow rate is zero, and the water level depth shown by the water level meter no longer changes, the control system (1) controls the extraction vacuum pump (15) to stop the extraction operation; After the extraction vacuum pump (15) is controlled to stop the extraction operation, the control system (1) simultaneously starts the inflation airbag pump (12) and the suction airbag pump (13) to open up the heterogeneous strata, so that the pollutants flow into the extraction pipe (4) along with the groundwater flow; While the control system (1) controls the inflation airbag pump (12) and the suction airbag pump (13) to start, if the air pressure in the inner cavity of the well pipe of the extraction well (2) indicated by the pressure gauge (11) shows an upward trend and the water level depth indicated by the water level gauge of the online monitoring device (16) shows a downward trend, the control system (1) controls the extraction vacuum pump (15) to start again to perform the extraction operation; While the extraction vacuum pump (15) is controlled to be turned on again, and the inflation airbag pump (12) and the suction airbag pump (13) are running, if the online monitoring device (16) shows that the site pollution characteristic index is no longer decreasing or the concentration rebounds and rises, the control system (1) controls the agent injection pump (14) to inject the agent until the online monitoring device (16) shows that the site pollution characteristic index reaches the remediation target value, stops the injection of the agent, and simultaneously shuts down the extraction vacuum pump (15), the inflation airbag pump (12) and the suction airbag pump (13).

2. The device according to claim 1, characterized in that The length of the medicine injection pipe (5) is at least 2 / 3 of the height of the auxiliary well (3); and the length of the first pump air pipe (6) is at least 2 / 3 of the height of the auxiliary well (3).

3. The device according to claim 1, characterized in that The inner diameter of the medicine injection tube (5) is equal to the inner diameter of the extraction tube (4).

4. The device according to claim 1, characterized in that With one of the extraction wells (2) as the center, at least three auxiliary wells (3) are arranged in a circumferential direction.

5. A method for intelligent multiphase extraction of groundwater based on the device according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Arranging an extraction well (2) and an auxiliary well (3) at a contaminated site, wherein the contaminated site is a low-permeability heterogeneous formation; S2, the control system (1) controls the extraction vacuum pump (15) to operate for a period of time T0, and the online monitoring device (16) feeds back the online monitoring data obtained within the time range T0 to the control system (1) in real time; during this process, the drug injection pump (14), the inflation airbag pump (12) and the suction airbag pump (13) are not operated; S3. Control system (1) makes on-site control based on the acquired data to achieve the treatment of underground pollutants.

6. The method according to claim 5, characterized in that The step S3 specifically includes: If the flow meter in the online monitoring device (16) shows that the flow rate is zero, and the water level depth shown by the water level meter no longer changes, the control system (1) controls the extraction vacuum pump (15) to stop the extraction operation.

7. The method according to claim 6, characterized in that The step S3 specifically includes: After controlling the extraction vacuum pump (15) to stop the extraction operation, the control system (1) simultaneously starts the inflation airbag pump (12) and the suction airbag pump (13) to open up the heterogeneous strata, allowing the pollutants to flow into the extraction pipe (4) along with the groundwater flow.

8. The method according to claim 7, characterized in that The step S3 specifically includes: While the control system (1) controls the inflation airbag pump (12) and the suction airbag pump (13) to start, if the air pressure in the inner cavity of the well pipe of the extraction well (2) displayed by the pressure gauge (11) shows an upward trend and the water level depth displayed by the water level gauge of the online monitoring device (16) shows a downward trend, the control system (1) controls the extraction vacuum pump (15) to start again to perform the extraction operation.

9. The method according to claim 8, characterized in that The step S3 specifically includes: While the extraction vacuum pump (15) is controlled to be turned on again, and the inflation airbag pump (12) and the suction airbag pump (13) are running, if the online monitoring device (16) shows that the site pollution characteristic index is no longer decreasing or the concentration rebounds and rises, the control system (1) controls the agent injection pump (14) to inject the agent until the online monitoring device (16) shows that the site pollution characteristic index reaches the remediation target value, stops the injection of the agent, and simultaneously shuts down the extraction vacuum pump (15), the inflation airbag pump (12) and the suction airbag pump (13).

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