CN113087043B

CN113087043B - Device and method for repairing underground water polluted by LNAPL (Low noise alkaline peroxide solution)

Info

Publication number: CN113087043B
Application number: CN202110449527.2A
Authority: CN
Inventors: 侯德义; 张琪; 王轶冬; 侯仁杰
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2021-04-25
Filing date: 2021-04-25
Publication date: 2022-06-21
Anticipated expiration: 2041-04-25
Also published as: CN113087043A

Abstract

The invention relates to a device and a method for repairing underground water polluted by LNAPL. The repairing device comprises an extraction pipe, a sleeve and an extraction box; the lower end pipe orifice of the extraction pipe penetrates through the sleeve and extends into the extraction box; the extraction box is provided with a first air channel and a second air channel, the first air channel is used for enabling the inner cavity of the extraction box to be communicated with the external area above the extraction box, and the second air channel is used for enabling the inner cavity of the extraction box to be communicated with the external area below the extraction box; in the process of descending the extraction box into the well, the first gas passing channel and the second gas passing channel are in an open state; in the extraction process of the extraction box, the first air channel and the second air channel are in a closed state. The repair device is convenient for efficiently extracting LNAPL phase pollutants which are scattered in LNAPL pollution sources and difficult to arrange extraction wells; the high-efficiency extraction of the LNAPL phase in a specific direction can be realized, the extraction effect of the LNAPL is enhanced, and the extraction of underground water in the extraction process is reduced.

Description

Device and method for repairing underground water polluted by LNAPL (Low noise alkaline peroxide solution)

Technical Field

The invention relates to the technical field of sewage treatment, in particular to a device and a method for repairing underground water polluted by LNAPL.

Background

The groundwater is used as an important drinking water source and natural resources in China, with the rapid development of society and economy in China, the groundwater pollution is increasingly serious due to the emission of important pollution sources mainly in petrochemical industry and other high-pollution industries, the groundwater remediation difficulty and cost are greatly increased due to the existence of high-concentration pollutants such as benzene, toluene, carbon tetrachloride and trichloroethylene, particularly LNAPL, which are mainly contained in the polluted groundwater, and the serious threat is formed on ecological safety, environmental safety, human residence safety and drinking water safety.

The groundwater pumping treatment technology is a groundwater remediation technology which is widely used and is characterized in that pumping wells are reasonably arranged in a pollution range of groundwater in a polluted site, polluted groundwater is pumped out of a water-bearing stratum through pumping equipment, and the groundwater is treated on the ground. However, the conventional underground water pumping treatment technology has the problems of long treatment and repair period, high repair long-term operation cost, trailing or rebounding underground water repair and the like when used for repairing the LNAPL polluted site.

Disclosure of Invention

In view of the above, it is necessary to provide a remediation device and a remediation method for groundwater contaminated by LNAPL.

A remediation apparatus for groundwater contaminated with LNAPL, the remediation apparatus comprising: the extraction pipe, the sleeve and the extraction box;

the lower end pipe orifice of the extraction pipe penetrates through the sleeve and extends into the extraction box;

the extraction box is connected with the extraction pipe and the sleeve, a first air channel and a second air channel are arranged on the extraction box, the first air channel is used for enabling the inner cavity of the extraction box to be communicated with the external area above the extraction box, and the second air channel is used for enabling the inner cavity of the extraction box to be communicated with the external area below the extraction box;

in the process of descending the extraction box, the first gas passing channel and the second gas passing channel are in an open state; in the extraction process of the extraction box, the first air-passing channel and the second air-passing channel are in a closed state.

In one embodiment, the extraction box comprises: the air-blocking device comprises a box body, an air-blocking plate and a water-blocking plate;

the top of the box body is provided with a first opening, and the bottom of the box body is provided with a second opening;

the choke plate is arranged at the first opening in a sealing way, and the choke plate is arranged at the second opening in a sealing way;

the first air channel is arranged on the air baffle plate, and the second air channel is arranged on the water baffle plate.

In one embodiment, the choke plate comprises a lower choke plate and an upper choke plate attached to the lower choke plate, the upper choke plate is connected with the sleeve and the box body, and the lower choke plate is rotatably arranged in the box body;

the gas barrier plate of lower floor is last to be provided with first the gas pocket of walking, it walks the gas pocket to be provided with the second on the gas barrier plate of upper strata, first walk the gas pocket with the cooperation of gas pocket is walked to the second constitutes first gas passage of walking, first walk the gas pocket can with the second walk the gas pocket and stagger in order to close first gas passage of walking, first walk the gas pocket can also with the second walk the gas pocket and overlap in order to open first gas passage of walking.

In one embodiment, a first gear is sleeved on the outer wall of the lower end pipe orifice of the extraction pipe, the lower gas baffle plate is sleeved on the lower end pipe orifice of the extraction pipe and provided with a second gear, and the first gear is meshed with the second gear;

when the extraction pipe rotates, the first gear drives the second gear to rotate, so that the lower-layer gas baffle plate is driven to rotate, and the first gas passing hole and the second gas passing hole are overlapped or staggered.

In one embodiment, the water-blocking plate comprises a lower water-blocking plate and an upper water-blocking plate attached to the lower water-blocking plate, the lower water-blocking plate is connected with the box body, and the upper water-blocking plate is positioned in the box body and is connected with the lower gas-blocking plate through a connecting rod;

the upper water-blocking plate is provided with a third air-passing hole, the lower water-blocking plate is provided with a fourth air-passing hole, the third air-passing hole and the fourth air-passing hole are matched to form the second air-passing channel, the third air-passing hole and the fourth air-passing hole are staggered to close the second air-passing channel, and the third air-passing hole and the fourth air-passing hole can be overlapped to open the second air-passing channel.

In one embodiment, the number of the first air holes, the second air holes, the third air holes and the fourth air holes is 4;

the first air holes are uniformly distributed along the circumferential direction of the lower air baffle plate, the second air holes are uniformly distributed along the axial direction of the upper air baffle plate, and the lower air baffle plate and the upper air baffle plate are coaxially distributed;

the third air holes are uniformly distributed along the circumferential direction of the upper water-blocking plate, the third air holes are uniformly distributed along the circumferential direction of the lower water-blocking plate, and the lower water-blocking plate and the upper water-blocking plate are coaxially distributed.

In one embodiment, the side wall of the upper choke plate is provided with a first annular groove, a first sealing element is arranged in the first annular groove, and the first sealing element is used for sealing a gap between the upper choke plate and the wall of the extraction well;

the side wall of the lower water-blocking plate is provided with a second annular groove, a second sealing element is arranged in the second annular groove, and the second sealing element is used for sealing a gap between the lower water-blocking plate and the wall of the extraction well.

In one embodiment, the side walls of the extraction box have a plurality of holes therein.

In one embodiment, an included angle of 30-180 degrees is formed between a connecting line between the sieve holes positioned on one outermost side in the circumferential direction and the axis in the extraction box and a connecting line between the sieve holes positioned on the other outermost side in the circumferential direction and the axis in the extraction box.

In one embodiment, the prosthetic device further comprises a hose and an elbow;

the hose is arranged at the lower end pipe orifice of the extraction pipe through a rotary joint;

the elbow is detachably arranged on the rotary joint and sleeved outside the hose, so that the pipe orifice of the hose points to the sieve pore, and transverse extraction is realized.

A remediation method of LNAPL contaminated groundwater, the remediation method comprising:

opening a first gas channel and a second gas channel of the extraction box, and lowering the extraction box into the extraction well through a casing pipe;

and when the extraction box is lowered to the LNAPL phase in the extraction well, closing the first gas passage and the second gas passage, and then extracting the LNAPL phase by using an extraction pipe.

According to the device and the method for restoring the underground water polluted by the LNAPL, in the process of descending the extraction box into the well, the first gas passage and the second gas passage of the extraction box are opened, so that the inner cavity of the extraction box is communicated with the upper external area and the lower external area of the extraction box, the internal pressure of the extraction box is ensured to be consistent with the external pressure, and the extraction box is smoothly descended to the LNAPL phase; in the process of extracting the LNAPL phase by the extraction box, the first air channel and the second air channel are closed, so that the extraction box forms a closed space, negative pressure is formed in the extraction box in the process of extraction, and underground water polluted by the LNAPL nearby is easier to gather towards the extraction box, so that the extraction efficiency is improved, the repair period of the underground water polluted by the LNAPL is shortened, and the pollution reduction of the underground water is efficiently realized; in addition, during extraction, the lower end face of the extraction box can be close to the bottom of the LNAPL phase as much as possible, so that the LNAPL phase can be ensured to be extracted as completely as possible and underground water can be prevented from being extracted, the underground water extraction proportion (namely water yield) in the extraction process is reduced, and the treatment cost of pollution after extraction is reduced.

Drawings

FIG. 1 is a schematic illustration of an embodiment of the present invention providing a remediation device for use with groundwater contaminated with LNAPL installed in an extraction well;

FIG. 2 is a cross-sectional view of a suitcase according to an embodiment of the present invention;

FIG. 3 is a cross-sectional view of a suitcase according to another embodiment of the present invention with the first and second air paths open;

FIG. 4 is a top view of a suitcase according to another embodiment of the present invention with a first air passage closed;

FIG. 5 is a top view of a suitcase according to another embodiment of the present invention with a first air passage open;

fig. 6 is a side view of an upper choke plate according to an embodiment of the present invention;

fig. 7 is a side view of a lower choke plate according to an embodiment of the invention;

FIG. 8 is a perspective view of a housing provided in accordance with an embodiment of the present invention;

FIG. 9 is a schematic diagram of an efficient well cluster configuration for source extraction of LNAPL wastewater provided in accordance with an embodiment of the present invention;

FIG. 10 is a top view of a housing provided in accordance with an embodiment of the present invention;

fig. 11 and 12 are schematic views illustrating an assembly of the swivel, the hose and the hose according to an embodiment of the present invention.

Wherein the reference numerals in the drawings are as follows:

100. an extraction pipe; 110. a first gear; 200. a sleeve; 300. a drawing box; 310. a box body; 310a, sieve holes; 311. a support table; 320. a choke plate; 321. a lower gas barrier; 321a, a first air outlet hole; 3211. a second gear; 3212. a mounting ring; 322. an upper gas barrier panel; 322a, a second air-passing hole; 322b, a first annular groove; 330. a water-blocking plate; 331. an upper water-blocking plate; 331a and a third air outlet; 332. a lower water blocking plate; 332a, a fourth air vent; 340. a connecting rod; 400. a hose; 500. bending the pipe; 600. a rotary joint; 700. a vacuum pump; 800. a wellhead seat; A. an extraction well; B. an LNAPL phase; C. ground water; D. an LNAPL sewage source.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, as those skilled in the art will recognize without departing from the spirit and scope of the present invention.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, or may be interconnected between two elements or in a relationship wherein the two elements interact, unless expressly limited otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

LNAPL (Light Non-aqueous Phase Liquids), which is lighter in density than water, typically floats on water. The LNAPL pollution is caused by leakage caused by corrosion of an oil storage tank and a pipeline or other reasons, and the LNAPL in the soil leaks downwards to pollute the underground water, so that the water safety and the crop safety are influenced.

At present, the commonly used groundwater pollution remediation technologies mainly comprise an in-situ oxidation technology, a heat treatment technology and a groundwater pumping treatment technology. The in-situ oxidation technology has wide applicability to groundwater organic pollution remediation, but has the problems of back diffusion, tailing, rebound, poor long-acting property, secondary pollution and the like in the removal of LNAPL pollutants, the mass transfer efficiency of an oxidant in a low-permeability stratum is often low, so that the in-situ oxidation remediation cost is increased, and meanwhile, the in-situ oxidation technology has the problem of degradation byproducts, so that secondary pollution can be caused. The heat treatment technology has the advantages of capability of in-situ remediation, wide applicable medium types, short remediation period, capability of synchronously treating polluted soil and underground water, suitability for high-concentration organic pollutants and the like, but the remediation cost is high, adverse effects on the environment of a treatment area and the surrounding area can be caused, and the use of the technology is limited to a certain extent. The groundwater pumping treatment technology is a groundwater remediation technology which is characterized in that pumping wells are reasonably arranged in the pollution range of the groundwater in a polluted site, the polluted groundwater is pumped out of an aquifer through pumping equipment and is treated on the ground, pollution plumes can be effectively controlled in a capture area, the diffusion range is reduced, and most pollutants can be rapidly removed. Wherein, a wellhead seat 800 (see fig. 1) is arranged at the wellhead of the extraction well and is used for installing a related water pumping device.

Referring to fig. 1, fig. 1 is a schematic structural diagram illustrating a remediation apparatus for groundwater C contaminated by LNAPL according to an embodiment of the present invention, and the remediation apparatus for groundwater C contaminated by LNAPL according to an embodiment of the present invention includes an extraction pipe 100, a casing 200, and an extraction tank 300; the lower end orifice of the extraction pipe 100 passes through the sleeve 200 and extends into the extraction box 300; the extraction box 300 is connected with the extraction pipe 100 and the sleeve 200, a first air channel and a second air channel are arranged on the extraction box 300, the first air channel is used for enabling the inner cavity of the extraction box 300 to be communicated with the external area above the extraction box 300, and the second air channel is used for enabling the inner cavity of the extraction box 300 to be communicated with the external area below the extraction box 300; in the process of descending the extraction box 300, the first gas passing channel and the second gas passing channel are in an open state; during the extraction process of the extraction box 300, the first air channel and the second air channel are in a closed state. The up and down orientation according to this embodiment is up to and down to the orientation the extraction tank 300 is pointing during extraction, i.e. up and down as shown in fig. 1. Wherein the inverted triangular lead of fig. 1 refers to the boundary of LNAPL phase B with groundwater C.

It is noted that the upper port of the casing 200 is mounted to the wellhead seat 800 of the extraction well a. Wherein, the upper end of the casing 200 can be connected with the wellhead seat 800 by a flange.

As an example, as shown in FIG. 1, the prosthetic device further includes a vacuum pump 700, and a suction port of the vacuum pump 700 communicates with the extraction tube 100. Vacuum pump 700 is used to pump LNAPL phase B from extraction well a. Alternatively, the vacuum pump 700 may be mounted on the wellhead seat 800.

In the remediation device for groundwater C polluted by LNAPL, as described above, in the process of descending the extraction tank 300, the first gas passage and the second gas passage of the extraction tank 300 are opened, so that the inner cavity of the extraction tank 300 is communicated with the upper and lower external areas of the extraction tank 300, and the internal pressure of the extraction tank 300 is ensured to be consistent with the external pressure, so that the extraction tank 300 smoothly descends into the LNAPL phase B; in the process of extracting the LNAPL phase B by the extraction tank 300, the first air passage and the second air passage are closed, so that the extraction tank 300 forms a closed space, negative pressure is formed in the extraction tank 300 in the process of extraction, and the groundwater C polluted by the LNAPL nearby is easier to converge towards the extraction tank 300, so that the extraction efficiency is improved, the repair period of the groundwater C polluted by the LNAPL is shortened, and the pollution reduction of the groundwater C is efficiently realized; in addition, during extraction, the lower end face of the extraction tank 300 can be as close to the bottom of the LNAPL phase B as possible, so that the LNAPL phase B can be ensured to be extracted as completely as possible and the groundwater C can be prevented from being extracted, the extraction ratio (namely the water yield) of the groundwater C in the extraction process is reduced, and the treatment cost of pollution after extraction is reduced.

In some embodiments of the present invention, as shown in FIG. 2, the extraction tank 300 includes: a case 310, a choke plate 320, and a water blocking plate 330; a first opening is formed in the top of the box body 310, and a second opening is formed in the bottom of the box body 310; the choke plate 320 is hermetically arranged at the first opening, and the choke plate 330 is hermetically arranged at the second opening; the first air passage is opened on the choke plate 320, and the second air passage is opened on the choke plate 330. The extraction box 300 with the structure is simple in structure and convenient to produce and process. It will be appreciated that the lower end nozzle of the extraction duct 100 extends into the tank body 310 of the extraction tank 300. Wherein the outer contour of the casing 310 may be adapted to the inner contour of the extraction well a, for example, if the extraction well a is a round well, the outer contour of the casing 310 is cylindrical.

In some embodiments of the present invention, as shown in fig. 3, the choke plate 320 includes a lower choke plate 321 and an upper choke plate 322 attached to the lower choke plate 321, the upper choke plate 322 is connected to the sleeve 200 and the housing 310, and the lower choke plate 321 is rotatably disposed in the housing 310; the lower gas barrier plate 321 is provided with a first gas passing hole 321a, the upper gas barrier plate 322 is provided with a second gas passing hole 322a, the first gas passing hole 321a and the second gas passing hole 322a cooperate to form a first gas passing channel, the first gas passing hole 321a can be staggered with the second gas passing hole 322a to close the first gas passing channel (see fig. 4), and the first gas passing hole 321a can also be overlapped with the second gas passing hole 322a to open the first gas passing channel (see fig. 3 and 5). Before the extraction box 300 goes down the well, the lower choke plate 321 is rotated until the first air-passing hole 321a is overlapped with the second air-passing hole 322a, so that the first air-passing channel is opened; after the extraction tank 300 is lowered into the LNAPL phase B, the lower choke plate 321 is rotated again until the first air vent 321a and the second air vent 322a are staggered, so as to close the first air vent channel.

The shape and size of the first air holes 321a and the second air holes 322a are not particularly limited in the embodiments of the present invention, as long as the first air holes 321a can overlap or be staggered with the second air holes 322 a. For example, the first air hole 321a and the second air hole 322a are both round holes and have the same size.

Optionally, the number of the first air holes 321a and the second air holes 322a is 4, the first air holes 321a are uniformly distributed along the circumferential direction of the lower air baffle 321, the second air holes 322a are uniformly distributed along the circumferential direction of the upper air baffle 322, and the lower air baffle 321 and the upper air baffle 322 are coaxially distributed. It can be understood that the distance between the first air holes 321a and the central axis of the lower air baffle 321 is equal to the distance between the second air holes 322a and the central axis of the upper air baffle 322. When the repair device is in a non-operating state, the lower choke plate 321 may be rotated until the first air holes 321a and the second air holes 322a are uniformly and alternately distributed along the circumferential direction, so as to close the first air passage. Then, when the extraction box is ready to go down the well, the lower choke plate 320 can be rotated by 45 ° in an instant or counterclockwise direction, so that the first air passing hole 321a and the second air passing hole 322a are communicated with each other, thereby opening the first air passing passage. When the extraction tank is down to the LNAPL phase B, the lower choke plate 320 continues to rotate by 45 degrees along the instantaneous or counterclockwise direction, and at this time, the first air outlet hole 321a and the second air outlet hole 322a can be judged to be staggered with each other, so that the first air outlet channel is closed.

As to how to rotate the lower choke plate 321, this embodiment gives an example, as shown in fig. 3, a first gear 110 is sleeved on an outer wall of a lower nozzle of the extraction pipe 100, the lower choke plate 321 is sleeved on the lower nozzle of the extraction pipe 100 and is provided with a second gear 3211, and the first gear 110 is engaged with the second gear 3211; when the extraction pipe 100 rotates, the first gear 110 drives the second gear 3211 to rotate, so as to drive the lower gas barrier 321 to rotate, such that the first gas passing hole 321a overlaps or is staggered with the second gas passing hole 322 a. The lower choke plate 321 does not need to be driven to rotate by an electric control device (for example, a motor and a communication device are installed in the housing 310), so that the problem that the electric control device cannot rotate the lower choke plate 321 due to water inflow can be avoided.

Optionally, the lower end nozzle of the extraction tube 100 is sealed through the upper choke plate 322 to ensure that the inner cavity of the extraction box 300 forms a closed space when the first air passage and the second air passage are in a closed state. Optionally, a sealing ring (e.g., a rubber ring) is disposed on an outer wall of the lower port of the extraction tube 100 to seal a gap between the outer wall of the lower port of the extraction tube 100 and the upper gas baffle 322.

Optionally, as shown in fig. 3, a support table 311 is disposed inside the box 310, a limit space is provided between the support table 311 and the upper choke plate 322, and the lower choke plate 321 is limited in the limit space. Therefore, in the process of rotating the extraction pipe 100, the first gear 110 can effectively drive the second gear 3211 to rotate, so as to drive the lower gas baffle 321 to rotate in the horizontal plane; in addition, the lower choke plate 321 can be kept in close contact with the upper choke plate 322 during rotation. The supporting platform 311 may be mounted in the box 310 by welding, casting, or the like.

Alternatively, as shown in fig. 3 and 7, a mounting ring 3212 is disposed on the bottom wall of the lower choke plate 321, and the second gear 3211 is disposed in the mounting ring 3212. The second gear 3211 is mounted on the lower choke plate 321 by the mounting ring 3212, and there is no need to provide an accommodating chamber for mounting the second gear 3211 by increasing the thickness of the lower choke plate 321, so that the lower choke plate 321 can be prevented from being excessively heavy. The mounting ring 3212 may be welded or cast to the lower baffle 321.

On the premise that the gas barrier plates 320 comprise an upper gas barrier plate 321 and a lower gas barrier plate 321, and the upper gas barrier plate 321 and the lower gas barrier plate 321 are respectively provided with a second air passing hole 322a and a first air passing hole 321a, as shown in fig. 3, the water barrier plate 330 comprises a lower water barrier plate 332 and an upper water barrier plate 331 attached to the lower water barrier plate 332, the lower water barrier plate 332 is connected with the box body 310, and the upper water barrier plate 331 is located in the box body 310 and connected with the lower gas barrier plate 321 through a connecting rod 340; the upper water-blocking plate 331 is provided with a third air-passing hole 331a, the lower water-blocking plate 332 is provided with a fourth air-passing hole 332a, the third air-passing hole 331a and the fourth air-passing hole 332a cooperate to form a second air-passing channel, the third air-passing hole 331a and the fourth air-passing hole 332a can be staggered to close the second air-passing channel, and the third air-passing hole 331a and the fourth air-passing hole 332a can be overlapped to open the second air-passing channel. In the process of rotating the lower choke plate 321, the lower choke plate 321 can drive the upper choke plate 331 to rotate through the connecting rod 340.

Optionally, the installation height of the lower water blocking plate 332 on the tank 310 is adjustable. The height of the lower water-blocking plate 332 and the distance between the lower water-blocking plate 332 and the upper gas-blocking plate 322 can be adjusted according to the position and the thickness of the LNAPL phase B, so that the highest liquid level of the LNAPL phase B is ensured to be positioned below the upper gas-blocking plate 322, and the lower water-blocking plate 332 is close to the lowest liquid level of the LNAPL phase B as much as possible. Illustratively, the lower water blocking plate 332 may be screwed into the tank 310 to achieve adjustment of the installation height thereof. In addition, the upper gas baffle 322 can adjust the height of itself in the extraction well a by adjusting the length of the sleeve 200. Illustratively, the casing 200 may be formed by connecting a plurality of sub-casings 200, and the number of the sub-casings 200 may be adjusted, so that the installation number of the sub-casings 200 may be adjusted according to the position of the LNAPL phase B.

Optionally, the number of the third air holes 331a and the number of the fourth air holes 332a are 4, the third air holes 331a are uniformly distributed along the circumferential direction of the upper water-blocking plate 331, the fourth air holes 332a are uniformly distributed along the circumferential direction of the lower water-blocking plate 332, and the upper water-blocking plate 331 and the lower water-blocking plate 332 are coaxially distributed. It can be understood that the distance between the third air hole 331a and the central axis of the upper water blocking plate 331 is equal to the distance between the fourth air hole 332a and the central axis of the lower water blocking plate 332. When the repair device is in a non-working state, the lower gas baffle 321 can be rotated until the first gas passing holes 321a and the second gas passing holes 322a are uniformly and alternately distributed along the circumferential direction, so that the first gas passing channel is closed; and the lower gas baffle 321 can drive the upper water baffle 331 to rotate in the rotating process, so that the third air holes 331a and the fourth air holes 332a are uniformly and alternately distributed along the circumferential direction, thereby closing the second air passing pipeline. Then, when the extraction box is ready to go down the well, the lower choke plate 320 can be rotated by 45 ° in an instant or counterclockwise direction, so that the first air passing hole 321a and the second air passing hole 322a can be communicated, and the first air passing channel is opened; and at the same time, the upper-layer air baffle 331 is driven by the lower-layer air baffle 321 to continue rotating in the same direction by 45 degrees, so that the second air channel is opened. When the pumping box is down to the LNAPL phase B, the lower choke plate 320 is continuously rotated by 45 degrees along the instantaneous or counterclockwise direction, at this time, the first air vent 321a and the second air vent 322a are mutually staggered, and the third air vent 331a and the fourth air vent 332a are mutually staggered, so that the first air channel and the second air channel are closed.

Optionally, as shown in fig. 6, the sidewall of the upper choke plate 322 has a first annular groove 322b, a first sealing member 323 is disposed in the first annular groove 322b, and the first sealing member 323 is used to seal a gap between the upper choke plate 322 and the wall of the extraction well a; the side wall of the lower water-blocking plate 332 is provided with a second annular groove, a second sealing element is arranged in the second annular groove, and the second sealing element is used for sealing a gap between the lower water-blocking plate 332 and the wall of the extraction well A. In this way, when the upper and

lower baffle plates

322, 332 reach the predetermined position, the pumping box 310 can be completely sealed at the predetermined position, so that gas or groundwater C can be effectively prevented from entering the box 310 during the pumping process. Optionally, the first annular groove 322b and the second annular groove are groove-shaped structures which are concave inwards and have semicircular cross sections. Optionally, the first seal 323 and the second seal are rubber rings, which may be adhered in the corresponding annular grooves.

In some embodiments of the present invention, as shown in fig. 8, the side wall of the extractor box 300 has a plurality of screen holes 310 a. Aiming at the LNAPL pollution source, the extraction wells A can be arranged in a plurality of plum blossom shapes and arranged around the LNAPL pollution source (see fig. 9), and the sieve holes 310a on the extraction box 300 in each extraction well A are adjusted to face the center of the LNAPL pollution source D, so that the LNAPL pollution source D can be effectively and quickly extracted, and the high-concentration pollutants can be quickly reduced.

Optionally, as shown in fig. 10, an included angle α of 30 ° to 180 ° is formed between a connecting line between the sieve hole 310a located on the outermost side in the circumferential direction and the central axis of the extraction box 300 and a connecting line between the sieve hole 310a located on the other outermost side in the circumferential direction and the central axis of the extraction box 300. The sieve holes 310a can set the size of the included angle α according to the purpose of extraction, for example, the included angle α is set to 30 °, 60 °, 90 °, 120 °, 150 °, 180 °, and the like, so as to further enhance the extraction of the LNAPL pollution source D in a specific direction.

Further, in some embodiments of the present invention, as shown in fig. 11 and 12, the prosthetic device further comprises a hose 400 and an elbow 500; the hose 400 is installed at the lower port of the extraction pipe 100 through the rotary joint 600; the elbow 500 is detachably installed on the rotary joint 600 and sleeved outside the hose 400 so that the nozzle of the hose 400 is directed to the sieve hole 310a, thereby performing the lateral extraction. It is understood that the bend 500 may be a 90 bend. During vertical extraction, elbow 500 does not need to be installed on swivel 600, and hose 400 is then slumped downward under the influence of gravity, thereby achieving vertical extraction. When performing lateral extraction, the elbow 500 is fitted over the outside of the hose 400 and mounted on the swivel 600 so as to orient the nozzle of the hose 400 from the vertical to the horizontal, and the swivel 600 is rotated according to the position of the LNAPL contamination source D to achieve suction in a specific direction.

Alternatively, as shown in fig. 11, the extraction nozzle of the hose 400 protrudes outside the elbow 500 and is a rigid nozzle.

In summary, the device for restoring groundwater C polluted by LNAPL provided by the embodiment of the invention is convenient for efficiently extracting LNAPL phase B pollutants which are scattered by an LNAPL pollution source D and difficult to lay an extraction well, especially for a site with a poor permeability coefficient; and the high-efficiency extraction of the LNAPL phase B in a specific direction can be realized, the extraction effect of the LNAPL is enhanced, and the extraction of the underground water C in the extraction process is reduced.

In another aspect, an embodiment of the present invention further provides a method for remediating LNAPL-contaminated groundwater C, which is implemented based on the remediation apparatus provided above, and the method includes:

step 100, opening a first gas passage and a second gas passage of the extraction box 300, and lowering the extraction box 300 into the extraction well through the casing 200.

Step 200, when the extraction tank 300 is lowered to the LNAPL phase B in the extraction well, the first gas passage and the second gas passage are closed, and then the LNAPL phase B is extracted by using the extraction pipe 100.

In the method for remedying the groundwater C polluted by the LNAPL, the first air channel and the second air channel of the extraction box 300 are opened in the process of descending the extraction box 300, so that the inner cavity of the extraction box 300 is communicated with the upper and lower outer areas of the extraction box 300, the internal pressure of the extraction box 300 is ensured to be consistent with the external pressure, and the extraction box 300 is smoothly descended to the LNAPL phase B; in the process of extracting the LNAPL phase B by the extraction tank 300, the first air passage and the second air passage are closed, so that the extraction tank 300 forms a closed space, negative pressure is formed in the extraction tank 300 in the process of extraction, and the groundwater C polluted by the LNAPL nearby is easier to converge towards the extraction tank 300, so that the extraction efficiency is improved, the repair period of the groundwater C polluted by the LNAPL is shortened, and the pollution reduction of the groundwater C is efficiently realized; in addition, during extraction, the lower end face of the extraction tank 300 can be as close to the bottom of the LNAPL phase B as possible, so that the LNAPL phase B can be ensured to be extracted as completely as possible and the groundwater C can be prevented from being extracted, the groundwater C extraction proportion (namely water yield) in the extraction process is reduced, and the treatment cost of pollution after extraction is reduced.

Before step S100, the repair method further includes: step S300, adjusting the length of the sleeve 200 and the installation height of the lower choke plate 321 of the extraction tank 300 on the tank 310 according to the position and thickness of the LNAPL phase B. This ensures that the highest level of LNAPL phase B is below the upper choke plate 322 and the lower choke plate 332 is as close as possible to the lowest level of LNAPL phase B.

All possible combinations of the technical features of the above embodiments may not be described for the sake of brevity, but should be considered as within the scope of the present disclosure as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A remediation device for remediation of groundwater contaminated with LNAPL, the remediation device comprising: an extraction tube (100), a sleeve (200) and an extraction box (300);

the lower end orifice of the extraction pipe (100) penetrates through the sleeve (200) and extends into the extraction box (300);

the extraction box (300) is connected with the extraction pipe (100) and the sleeve (200), a first air channel and a second air channel are arranged on the extraction box (300), the first air channel is used for enabling the inner cavity of the extraction box (300) to be communicated with the outer area above the extraction box (300), and the second air channel is used for enabling the inner cavity of the extraction box (300) to be communicated with the outer area below the extraction box (300);

during the process of descending the extraction box (300), the first gas passage and the second gas passage are in an open state; in the extraction process of the extraction box (300), the first air-passing channel and the second air-passing channel are in a closed state.

2. The prosthetic device according to claim 1, characterized in that the extraction tank (300) comprises: a box body (310), a choke plate (320) and a water-blocking plate (330);

the top of the box body (310) is provided with a first opening, and the bottom of the box body (310) is provided with a second opening;

the choke plate (320) is arranged at the first opening in a sealing mode, and the choke plate (330) is arranged at the second opening in a sealing mode;

the first air channel is arranged on the choke plate (320), and the second air channel is arranged on the choke plate (330).

3. The prosthetic device of claim 2, wherein the choke plate (320) comprises a lower choke plate (321) and an upper choke plate (322) attached to the lower choke plate (321), the upper choke plate (322) is connected to the sleeve (200) and the housing (310), and the lower choke plate (321) is rotatably disposed in the housing (310);

be provided with first air pocket (321 a) of walking on lower floor's choke board (321), it walks air pocket (322 a) to be provided with the second on upper air pocket (322), first air pocket (321 a) of walking with air pocket (322 a) cooperation constitution is walked to the second first, first air pocket (321 a) of walking can with air pocket (322 a) are walked to the second staggers in order to close first air pocket of walking, first air pocket (321 a) of walking can also with air pocket (322 a) overlap in order to open first air pocket of walking.

4. The prosthetic device according to claim 3, characterized in that the outer wall of the lower nozzle of the extraction pipe (100) is sleeved with a first gear (110), the lower choke plate (321) is sleeved on the lower nozzle of the extraction pipe (100) and is provided with a second gear (3211), and the first gear (110) is meshed with the second gear (3211);

when the extraction pipe (100) rotates, the first gear (110) drives the second gear (3211) to rotate, so as to drive the lower gas barrier plate (321) to rotate, so that the first gas passing hole (321 a) and the second gas passing hole (322 a) are overlapped or staggered.

5. The prosthetic device according to claim 3, characterized in that the water-blocking plate comprises a lower water-blocking plate (332) and an upper water-blocking plate (331) attached to the lower water-blocking plate (332), the lower water-blocking plate (332) is connected to the tank (310), the upper water-blocking plate (331) is located in the tank (310) and connected to the lower water-blocking plate (321) through a connecting rod (340);

the upper water-blocking plate (331) is provided with a third air-passing hole (331 a), the lower water-blocking plate (332) is provided with a fourth air-passing hole (332 a), the third air-passing hole (331 a) and the fourth air-passing hole (332 a) are matched to form the second air-passing channel, the third air-passing hole (331 a) and the fourth air-passing hole (332 a) can be staggered to close the second air-passing channel, and the third air-passing hole (331 a) can be overlapped with the fourth air-passing hole (332 a) to open the second air-passing channel.

6. The prosthetic device according to claim 5, characterized in that the number of the first air-passing holes (321 a), the second air-passing holes (322 a), the third air-passing holes (331 a) and the fourth air-passing holes (332 a) is 4;

the first air holes (321 a) are uniformly distributed along the circumferential direction of the lower air baffle plate (321), the second air holes (322 a) are uniformly distributed along the axial direction of the upper air baffle plate (322), and the lower air baffle plate (321) and the upper air baffle plate (322) are coaxially distributed;

the third air holes (331 a) are uniformly distributed along the circumferential direction of the upper water-blocking plate (331), the third air holes (331 a) are uniformly distributed along the circumferential direction of the lower water-blocking plate (332), and the lower water-blocking plate (332) and the upper water-blocking plate (331) are coaxially distributed.

7. The prosthetic device of claim 5, characterized in that the side wall of the upper choke plate (322) has a first annular groove (322 b), a first sealing element (323) is arranged in the first annular groove (322 b), the first sealing element (323) is used for sealing the gap between the upper choke plate (322) and the wall of the extraction well (A);

the side wall of the lower water-blocking plate (332) is provided with a second annular groove, a second sealing element is arranged in the second annular groove, and the second sealing element is used for sealing a gap between the lower water-blocking plate (332) and the wall of the extraction well (A).

8. The prosthetic device according to any one of claims 1-7, characterized in that the side wall of the extraction tank (300) is provided with a plurality of sieve holes (310 a).

9. The prosthetic device according to claim 8, characterized in that an angle α of 30 ° to 180 ° is formed between a line connecting one of the circumferentially outermost screen holes (310 a) to the central axis of the extraction box (300) and a line connecting the other circumferentially outermost screen hole (310 a) to the central axis of the extraction box (300).

10. The prosthetic device of claim 8, further comprising a hose (400) and an elbow (500);

the hose (400) is arranged at the lower end nozzle of the extraction pipe (100) through a rotary joint (600);

the elbow (500) is detachably arranged on the rotary joint (600) and sleeved outside the hose (400) so that the nozzle of the hose (400) points to the sieve pore (310 a) to realize transverse extraction.

11. A remediation method for groundwater contaminated with LNAPL, applied to a remediation apparatus for groundwater contaminated with LNAPL as claimed in any one of claims 1 to 10, the remediation method comprising:

opening a first gas channel and a second gas channel of the extraction box (300), and lowering the extraction box (300) into the extraction well (A) through a casing (200);

and when the extraction box (300) is lowered to the LNAPL phase (B) in the extraction well (A), the first gas passage and the second gas passage are closed, and then the LNAPL phase (B) is extracted by using an extraction pipe (100).