A low disturbance precision extraction device for dnaps in groundwater

Abstract

The present application relates to a kind of low disturbance precision extraction device of DNAPLs in groundwater, including extraction pipe, oil extraction assembly and oil outlet assembly, linkage assembly is arranged in extraction pipe, control feedback component is arranged in cooperation with linkage assembly;Extraction pipe is explored into groundwater with preset speed, control feedback component works, under preset starting condition, oil extraction assembly is opened in positive direction, oil outlet assembly is closed, DNAPLs is extracted and temporarily stored, reaches preset switching condition, oil extraction assembly is opened in reverse direction, oil outlet assembly is opened, DNAPLs is discharged;Repeat action until DNAPLs is extracted.The present application can meet the needs of extracting DNAPLs of different depths by adjusting air pressure, can accurately extract DNAPLs, reduce disturbance to groundwater, avoid pollution diffusion;Equipment maintenance cost is less, basically no waste water extraction, comprehensive treatment cost is low;High degree of intelligence, convenient to use, with good application prospect.

Description

Technical Field

[0001] This invention relates to the technical field of water, wastewater, sewage or sludge treatment, and particularly to a low-disturbance precision extraction device for DNAPLs in groundwater. Background Technology

[0002] Dense non-aqueous phase liquids (DNAPLs) are a common type of organic pollutant among many substances that cause groundwater pollution. They are organic compounds with a specific gravity greater than 1 and contain one or more chlorine, bromine, or fluorine atoms. They are commonly found in groundwater at decommissioned sites of key industries such as petrochemicals, pharmaceuticals, and pesticides.

[0003] For DNAPLs contamination, traditional treatment methods primarily rely on multiphase extraction technology. This involves vacuum extraction, using specialized equipment such as jet pumps to extract non-aqueous liquids and contaminated groundwater together. The extracted soil gases, groundwater, and oil slicks from the contaminated area are then separated and treated at the surface to control and remediate organic pollutants in the soil and groundwater, achieving site remediation. The extracts obtained through multiphase separation require gas-liquid and liquid-liquid separation processes. The separated gas enters a gas treatment unit, while the liquid is treated using other methods. The oil-water mixture can be treated using gravity sedimentation to remove the oil slick and separate water with low oil content.

[0004] However, the shortcomings of existing technologies lie in the significant disturbance to groundwater and the large volume of wastewater that can be treated using multiphase extraction. For example, Chinese patent CN113800657A discloses a method and device for in-situ treatment of DNAPLs in groundwater. This method involves extending an absorption pipe to the bottom of an extraction well, introducing an absorbent into the pipe, and then aerating it. After aeration, the absorbent is extracted. The DNAPLs phase is treated using physical absorption, with aeration causing the bottom DNAPLs phase to churn and come into contact with the absorbent in the pipe. While this method can significantly reduce treatment costs and remove the DNAPLs phase, it excessively disturbs the groundwater, potentially causing the spread of pollutants and increasing the difficulty of remediation. Currently, there are also treatment methods that use vacuum pumps and centrifugal pumps to directly extract DNAPLs, but these often have shallow extraction depths and limited application ranges, all of which affect the final treatment effect. Summary of the Invention

[0005] This invention solves the problems existing in the prior art and provides a low-disturbance, precise extraction device for DNAPLs in groundwater.

[0006] The technical solution adopted in this invention is a low-disturbance precision extraction device for DNAPLs in groundwater. The device includes an extraction pipe, an oil extraction component and an oil discharge component are provided in conjunction with the extraction pipe, a linkage component is provided in the extraction pipe in conjunction with the oil extraction component and the oil discharge component, and a control feedback component is provided in conjunction with the linkage component.

[0007] The extraction tube is inserted into the groundwater at a preset speed. The control feedback component is activated, and under preset start-up conditions, the control linkage component is activated. The oil extraction component is activated in the forward direction, and the oil discharge component is activated, in order to extract and temporarily store DNAPLs. After the preset switching conditions are met, the control linkage component is activated, the oil extraction component is activated in the reverse direction, and the oil discharge component is activated, and the DNAPLs are discharged. The extraction tube is inserted into the groundwater again at a preset speed, and the action is repeated until all the DNAPLs are extracted.

[0008] Preferably, the extraction tube includes an outer tube for extracting and temporarily storing DNAPLs and an inner tube for discharging DNAPLs, with an oil extraction assembly configured in conjunction with the outer tube and an oil discharging assembly configured in conjunction with the inner tube.

[0009] Preferably, the upper ends of the inner tube and the outer tube are flush, the axial distance between the inner tube and the outer tube is greater than 0, the length of the inner tube is less than the length of the outer tube, and a linkage component is provided between the lower ends of the inner tube and the outer tube.

[0010] Preferably, the oil outlet assembly includes a DNAPLs outlet located at the top of the inner tube, and the oil extraction assembly includes a gas inlet and outlet located at the top of the outer tube. The distance between the DNAPLs outlet and the gas inlet and outlet is greater than 0. The top of the extraction tube, except for the DNAPLs outlet and the gas inlet and outlet, is provided with a top plate. A gas source is connected in conjunction with the gas inlet and outlet.

[0011] Preferably, the linkage component includes a first air valve and a second air valve respectively located at the bottom of the inner tube and the outer tube.

[0012] Preferably, the first air valve includes a first stepped hole at the bottom of the inner tube, the upper diameter of the first stepped hole is larger than the lower diameter, a first valve ball is provided in the upper part of the first stepped hole, and a first limiting member is provided at the top of the first stepped hole.

[0013] Preferably, the second air valve includes a second stepped hole at the bottom of the outer pipe, the upper diameter of the second stepped hole is larger than the lower diameter, a second valve ball is provided in the upper part of the second stepped hole, and a second limiting member is provided at the top of the second stepped hole.

[0014] Preferably, a screen is provided at the bottom of the extraction tube.

[0015] Preferably, the control feedback component includes an interface sensor located at the bottom of the extraction pipe, used to determine the oil-water interface and provide feedback after the extraction pipe is inserted into the groundwater at a preset speed.

[0016] Preferably, the control feedback component further includes one or more liquid level sensors disposed on the inner wall of the outer tube, used to determine the liquid level height in the outer tube under the working state of the oil pumping or oil discharging component.

[0017] This invention relates to a low-disturbance, precise extraction device for DNAPLs from groundwater, comprising an extraction pipe, an oil extraction component and an oil discharge component, both connected within the extraction pipe, and a linkage component and a control feedback component. The extraction pipe is inserted into the groundwater at a preset speed. The control feedback component operates, and under preset activation conditions, the linkage component is activated, turning on the oil extraction component in the forward direction and closing the oil discharge component to extract and temporarily store DNAPLs. Upon reaching a preset switching condition, the linkage component is activated, turning on the oil extraction component in the reverse direction and opening the oil discharge component, discharging the DNAPLs. The extraction pipe is then inserted into the groundwater again at the preset speed, and the process is repeated until all DNAPLs are extracted.

[0018] The beneficial effects of this invention are as follows:

[0019] (1) Using air pressure as the power source, the need to extract DNAPLs at different depths can be met by adjusting the air pressure, thus solving the limitation of traditional equipment in terms of treatment depth;

[0020] (2) A pneumatic extraction method is adopted, supplemented by an interface sensor for detecting the oil-water interface, which is used to locate the depth of DNAPLs. This method can accurately extract DNAPLs, reduce disturbance to groundwater, and avoid pollution spread.

[0021] (3) The equipment maintenance cost is low, there is basically no wastewater extraction, and the overall treatment cost is low;

[0022] (4) It has a high degree of intelligence, is easy to use, and has good application prospects. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the present invention;

[0024] Figure 2 for Figure 1 A partially enlarged structural diagram of part A shown;

[0025] Figure 3 for Figure 2 Schematic diagram of the structure in the BB-direction section;

[0026] Figure 4This is a schematic diagram of the present invention in operation, wherein (a) is a schematic diagram of the oil extraction component being turned on in the forward direction and the oil outlet component being turned off, and (b) is a schematic diagram of the oil extraction component being turned on in the reverse direction and the oil outlet component being turned off. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to embodiments, but the scope of protection of the present invention is not limited thereto.

[0028] This invention relates to a low-disturbance precision extraction device for DNAPLs in groundwater. The device includes an extraction pipe, an oil extraction component and an oil discharge component are provided in conjunction with the extraction pipe, a linkage component is provided in the extraction pipe in conjunction with the oil extraction component and the oil discharge component, and a control feedback component is provided in conjunction with the linkage component.

[0029] The extraction tube is inserted into the groundwater at a preset speed. The control feedback component is activated, and under preset start-up conditions, the control linkage component is activated. The oil extraction component is activated in the forward direction, and the oil discharge component is activated, in order to extract and temporarily store DNAPLs. After the preset switching conditions are met, the control linkage component is activated, the oil extraction component is activated in the reverse direction, and the oil discharge component is activated, and the DNAPLs are discharged. The extraction tube is inserted into the groundwater again at a preset speed, and the action is repeated until all the DNAPLs are extracted.

[0030] The technical principle of this invention is as follows: with the assistance of a control feedback component, the oil extraction component controls the inlet and outlet of air, and the oil outlet component works in conjunction to control the flow direction of DNAPLs under the control of the inlet and outlet of air, thereby achieving low-disturbance and precise extraction of DNAPLs. Specifically, the extraction tube is inserted into the groundwater at a preset speed to avoid excessive disturbance to the area to be treated. At the same time, the control feedback component works and sets a preset start condition, which in this case is reaching the middle position of the DNAPLs layer. After the start condition is triggered, the control linkage component works, the oil extraction component opens in the forward direction and the oil outlet component closes, and the DNAPLs are extracted into the extraction tube and temporarily stored. When the preset switching condition is reached, which is generally controlled by the liquid level of DNAPLs in the extraction tube, the control linkage component works, the oil extraction component opens in the reverse direction and the oil outlet component opens, and the DNAPLs are discharged from the extraction tube for subsequent processing. This process is repeated until all the DNAPLs are extracted.

[0031] During the processing of this invention, the disturbance to DNAPLs is almost zero, the extracted DNAPLs contain little wastewater, and different extraction depths can be switched at will, making it very convenient to use.

[0032] The extraction tube includes an outer tube 1 for extracting and temporarily storing DNAPLs and an inner tube 2 for discharging DNAPLs. An oil extraction assembly is configured in conjunction with the outer tube 1, and an oil discharge assembly is configured in conjunction with the inner tube 2.

[0033] The upper ends of the inner tube 2 and the outer tube 1 are flush, the axial distance between the inner tube 2 and the outer tube 1 is greater than 0, the length of the inner tube 2 is less than the length of the outer tube 1, and a linkage component is provided between the lower ends of the inner tube 2 and the outer tube 1.

[0034] In this invention, specifically, the extraction tube is a combination of an outer tube 1 and an inner tube 2. The two are not coaxial and their upper ends are flush, while their lower ends are at a distance difference. This structure allows the extracted DNAPLs to be temporarily stored in the outer tube 1 outside the inner tube 2, and after a certain amount has been stored, they are discharged through the inner tube 2.

[0035] The oil outlet assembly includes a DNAPLs outlet 3 located at the top of the inner tube 2, and the oil extraction assembly includes a gas inlet / outlet 4 located at the top of the outer tube 1. The distance between the DNAPLs outlet 3 and the gas inlet / outlet 4 is greater than 0. The top of the extraction tube, except for the DNAPLs outlet 3 and the gas inlet / outlet 4, is provided with a top plate 5. A gas source 6 is connected in conjunction with the gas inlet / outlet 4.

[0036] The linkage component includes a first air valve 7 and a second air valve 8 respectively located at the bottom of the inner tube 2 and the outer tube 1.

[0037] The first air valve 7 includes a first stepped hole 71 located at the bottom of the inner tube 2. The upper diameter of the first stepped hole 71 is larger than the lower diameter. A first valve ball 72 is provided in the upper part of the first stepped hole 71, and a first limiting member 73 is provided at the top of the first stepped hole 71.

[0038] The second air valve 8 includes a second stepped hole 81 located at the bottom of the outer tube 1. The upper diameter of the second stepped hole 81 is larger than the lower diameter. A second valve ball 82 is provided in the upper part of the second stepped hole 81, and a second limiting member 83 is provided at the top of the second stepped hole 81.

[0039] In this invention, the linkage of the linkage components, in conjunction with the inner tube 2 and the outer tube 1, is specifically implemented as follows:

[0040] The oil extraction assembly has a dedicated gas inlet / outlet 4 at the top of the outer pipe 1, and is connected to the gas source 6. The gas source 6 can transfer gas back and forth between the gas inlet / outlet 4. Generally, the gas source 6 is a combination of a vacuum pump and an air compressor (not shown in the figure). The vacuum pump provides negative pressure conditions, and the air compressor provides positive pressure conditions.

[0041] When the oil extraction assembly needs to be operated in the forward direction, the oil extraction assembly is opened in the forward direction and the oil outlet assembly is closed. That is, air is extracted from the gas inlet and outlet 4 through the gas source 6, the air pressure in the outer pipe 1 outside the inner pipe 2 decreases, and then the first valve ball 72 at the first gas valve 7 blocks the corresponding position of the first step hole 71, the oil outlet assembly is closed, and the second valve ball 82 at the second gas valve 8 rises and is restricted in the second step hole 81 by the second limiting member 83, the oil extraction assembly is opened, and at this time DNAPLs begin to enter the outer pipe 1 outside the inner pipe 2.

[0042] When the conditions for DNAPLs discharge are met, the oil extraction assembly needs to be reversed. At this time, the oil extraction assembly is reversed and the oil outlet assembly is opened. That is, gas is injected into the gas inlet and outlet 4 through the gas source 6. At this time, the gas pressure in the outer pipe 1 outside the inner pipe 2 increases, and the second valve ball 82 at the second gas valve 8 falls down and blocks the corresponding position of the second step hole 81. The second gas valve 8 is closed, while the first valve ball 72 at the first gas valve 7 rises and is restricted by the first limiting member 73 within the first step hole 71. The oil extraction assembly is reversed and the DNAPLs in the outer pipe 1 outside the inner pipe 2 flow from the first gas valve 7 into the inner pipe 2 and are finally discharged from the DNAPLs discharge outlet 3.

[0043] In this invention, the first limiting member 73 and the second limiting member 83 can be set above the corresponding stepped hole in the form of a circular hoop. A stop block is set at the position of the circular hoop facing the axis of the stepped hole, so that the corresponding valve ball can only pass through partially and then block the stepped hole. This can be achieved by the corresponding structure of the stop block and the stepped hole. This is something that those skilled in the art can easily understand, and they can set it themselves according to their needs.

[0044] In this invention, obviously, in order to better realize the function of the linkage component, a sealed top plate 5 is provided on the top of the extraction tube except for the DNAPLs outlet 3 and the gas inlet and outlet 4, and the extraction tube is completely sealed except for the two gas valves, the DNAPLs outlet 3 and the gas inlet and outlet 4.

[0045] The bottom of the extraction tube is equipped with a screen 9.

[0046] In this invention, a screen 9, typically 50-100 mesh, is installed at the bottom of the extraction tube. This screen is suitable for DNAPLs of various viscosities and prevents sand particles from entering the device, thus affecting its working efficiency and service life. In practical applications, the screen 9 is placed at the bottom of the extraction tube rather than at the bottom of the second step hole 81 of the second air valve 8 to ensure that the force-bearing surface of the screen 9 is larger and to prevent it from breaking during repeated operations.

[0047] The control feedback component includes an interface sensor 10 located at the bottom of the extraction pipe, which is used to determine the oil-water interface and provide feedback after the extraction pipe is inserted into the groundwater at a preset speed.

[0048] The control feedback component also includes one or more liquid level sensors 11 installed on the inner wall of the outer pipe 1, used to determine the liquid level height in the outer pipe 1 under the working state of the oil pumping or oil discharging component.

[0049] In this invention, the interface sensor 10 is generally an oil-water interface probe, which is used to determine the location of DNAPLs and achieve precise extraction. Generally speaking, its application scenarios are relatively complex. Considering that oil extraction will reduce the thickness of the oil layer and cause the interface on the oil phase to continue to decline, it is necessary to repeatedly adjust the working position of the oil extraction component.

[0050] In this invention, the liquid level sensor 11 exists in the form of an alarm probe, used to monitor the liquid level of DNAPLs in real time and prevent them from entering the gas source 6, etc., and causing damage to other equipment.

[0051] like Figure 4 As shown, the control method of the low-disturbance precision extraction device for DNAPLs in groundwater according to the present invention includes the following steps:

[0052] S1. Set up groundwater wells for pre-detection, analyze groundwater morphology, and determine the estimated distribution of DNAPLs.

[0053] S2 lowers the extraction pipe into the groundwater well at a preset speed. Generally, there is a maximum speed limit to prevent it from disturbing the groundwater environment.

[0054] S3 acquires the feedback signal from the sensor in real time. When the interface sensor 10 passes through the first oil-water interface, it indicates that it has entered DNAPLs from groundwater, and the depth D1 is recorded. The extraction tube continues to descend slowly. When the interface sensor 10 passes through the second oil-water interface, that is, when it is at the bottom of the DNAPLs, the depth D2 is recorded. The thickness L of the DNAPLs at the current position is estimated based on the two depth values. L = D2 - D1.

[0055] S4 Pull up the extraction tube until the sieve 9 position reaches the middle position of the DNAPLs oil layer, i.e., D1+ L / 2;

[0056] After S5 stabilizes, start the gas source 6, close the first gas valve 7, open the second gas valve 8, and the DNAPLs are drawn into the outer tube 1 outside the inner tube 2. Figure 4 As shown in the gray part of (a); the liquid level value of DNAPLs is acquired in real time during the process. When the liquid level rises to the uppermost liquid level sensor 11, the pumping stops and the mode is switched, and the gas source 6 starts to output gas.

[0057] S6 As the internal air pressure of the outer tube 1 increases, the first air valve 7 opens and the second air valve 8 closes. DNAPLs in the outer tube 1, outside the inner tube 2, are forced into the inner tube 2 through the first stepped hole 71 of the first air valve 7. Figure 4 The gray area in (b) is shown;

[0058] S7 When the DNAPLs liquid level in the outer tube 1 drops to the lowest level sensor 11, i.e. the lower limit alarm probe, an oil shortage alarm can be issued and the gas injection can be stopped.

[0059] S8 will move the extraction tube downwards at a preset speed and repeat S3 until, in oil extraction mode, the intelligent control center displays that the outer tube 1 is always in a state of oil shortage, indicating that the oil layer has been completely extracted.

[0060] During the repeat of S3, the total amount of DNAPLs at the current site can be estimated by measuring the differences in D1, D2, and L values, combined with the volume in the outer tube 1 outside the inner tube 2, and the treatment plan can be adjusted accordingly.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A low-disturbance, precise extraction device for DNAPLs from groundwater, characterized in that: The device includes an extraction tube, an oil extraction assembly and an oil outlet assembly are provided in conjunction with the extraction tube, a linkage assembly is provided inside the extraction tube in conjunction with the oil extraction assembly and the oil outlet assembly, and a control feedback assembly is provided in conjunction with the linkage assembly. The extraction tube includes an outer tube for extracting and temporarily storing DNAPLs and an inner tube for discharging DNAPLs. An oil extraction assembly is configured in conjunction with the outer tube, and an oil outlet assembly is configured in conjunction with the inner tube. The oil outlet assembly includes a DNAPLs outlet located at the top of the inner tube, and the oil extraction assembly includes a gas inlet and outlet located at the top of the outer tube. A gas source is connected in conjunction with the gas inlet and outlet. The linkage component includes a first air valve and a second air valve respectively located at the bottom of the inner tube and the outer tube. The control feedback component includes an interface sensor located at the bottom of the extraction pipe, used to determine the oil-water interface and provide feedback after the extraction pipe is inserted into the groundwater at a preset speed; it also includes one or more liquid level sensors located on the inner wall of the outer pipe, used to determine the liquid level height in the outer pipe when the oil extraction component or the oil discharge component is in operation. The extraction tube is inserted into the groundwater at a preset speed. The control feedback component works, and under the preset start-up conditions, the control linkage component works. The oil extraction component is turned on in the forward direction and the oil discharge component is turned off to extract and temporarily store DNAPLs. After the preset switching conditions are met, the control linkage component works, the oil extraction component is turned on in the reverse direction and the oil discharge component is turned on, and the DNAPLs are discharged. The extraction tube is then inserted into the groundwater again at a preset speed, and the process is repeated until all DNAPLs are extracted.

2. The low-disturbance precision extraction device for DNAPLs in groundwater according to claim 1, characterized in that: The upper ends of the inner and outer tubes are flush, the axial distance between the inner and outer tubes is greater than 0, the length of the inner tube is less than the length of the outer tube, and a linkage component is provided between the lower ends of the inner and outer tubes.

3. The low-disturbance precision extraction device for DNAPLs in groundwater according to claim 1, characterized in that: The distance between the DNAPLs discharge port and the gas inlet / outlet is greater than 0, and the top of the extraction pipe, except for the DNAPLs discharge port and the gas inlet / outlet, is equipped with a top plate.

4. The low-disturbance precision extraction device for DNAPLs in groundwater according to claim 1, characterized in that: The first air valve includes a first stepped hole at the bottom of the inner tube. The upper diameter of the first stepped hole is larger than the lower diameter. A first valve ball is provided in the upper part of the first stepped hole, and a first limiting member is provided at the top of the first stepped hole.

5. The low-disturbance precision extraction device for DNAPLs in groundwater according to claim 1, characterized in that: The second air valve includes a second stepped hole at the bottom of the outer tube. The upper diameter of the second stepped hole is larger than the lower diameter. A second valve ball is provided in the upper part of the second stepped hole, and a second limiting member is provided at the top of the second stepped hole.

6. The low-disturbance precision extraction device for DNAPLs in groundwater according to claim 1, characterized in that: The bottom of the extraction tube is equipped with a screen.

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