A contaminated groundwater repair device and repair method

Abstract

The present invention belongs to the field of groundwater remediation, and discloses a contaminated groundwater remediation device and a remediation method, which can effectively expand the remediation range and improve the remediation efficiency. The contaminated groundwater remediation device includes a horizontally arranged injection well, a horizontally arranged extraction well, a treatment device, an injection pump and an extraction pump, wherein the injection well is located above the extraction well; the extraction pump is located in the extraction well, the extraction pump is connected to the water inlet end of the treatment device, and the extraction pump is used to transport the contaminated groundwater in the extraction well to the treatment device; the injection pump is connected to the water outlet end of the treatment device, and the injection pump is used to inject the groundwater after the treatment device is repaired into the injection well.

Description

Technical Field

[0001] The present invention belongs to the field of groundwater remediation, and in particular, relates to a contaminated groundwater remediation device and a remediation method. Background Art

[0002] Contaminated groundwater poses great potential hazards to human health, the ecological environment, etc., and needs to be given great attention. In order to meet this challenge, engineering and technical personnel have developed a variety of remediation technologies, among which the vertical circulation well technology is an in-situ groundwater remediation method. It sets a vertical well structure in the contaminated area to promote the circulation of groundwater and accelerate the removal of pollutants. In this method, the contaminated groundwater flows in a nearly horizontal direction in the formation, and is pumped out for treatment after merging into the vertical well. However, this technology has the problem that the remediation range of a single circulation well is small, and the disposal efficiency of non-aqueous phase pollutants is low, especially. In addition, the vertical circulation well needs to occupy a large area of ​​ground surface, which makes it difficult to apply to the remediation of groundwater in contaminated sites of production enterprises. Therefore, it is urgent to develop new contaminated groundwater remediation devices and remediation methods to improve the remediation effect of contaminated groundwater. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a contaminated groundwater repair device and a repair method, which can effectively expand the repair range and improve the repair efficiency.

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

[0005] On the one hand, the present invention provides a contaminated groundwater remediation device, comprising a horizontally arranged injection well, a horizontally arranged extraction well, a treatment device, an injection pump and an extraction pump, wherein the injection well is located above the extraction well; the extraction pump is located in the extraction well, the extraction pump is connected to the water inlet end of the treatment device, and the extraction pump is used to transport the contaminated groundwater in the extraction well to the treatment device; the injection pump is connected to the water outlet end of the treatment device, and the injection pump is used to inject the groundwater repaired by the treatment device into the injection well.

[0006] As a preferred example, the injection well comprises a first connecting part and an injection part which are connected and communicated with each other, and the tube wall of the injection part is provided with a first sieve hole; the extraction well comprises a second connecting part and an extraction part which are connected and communicated with each other, and the tube wall of the extraction part is provided with a second sieve hole.

[0007] As a preferred example, the first sieve holes are evenly distributed on the tube wall of the injection part, and two adjacent rows of first sieve holes are staggered; the second sieve holes are evenly distributed on the tube wall of the extraction part, and two adjacent rows of second sieve holes are staggered.

[0008] As a preferred example, the length of the injection portion is 0.5 to 0.8 times the length of the contaminated area, and the length of the contaminated area is the distance of the contaminated groundwater along the groundwater flow direction.

[0009] As a preferred example, the length of the extraction portion According to formula (1) and formula (2), it is calculated as follows:

[0010] Formula (1)

[0011] Formula (2)

[0012] In the formula, is the length adjustment coefficient of the extraction section, in m; It is the spatial adjustment partial coefficient that affects the extraction section length adjustment coefficient, dimensionless; is the vertical distance between the injection part and the extraction part, in meters; It is the head adjustment partial coefficient that affects the extraction section length adjustment coefficient, dimensionless; The difference between the groundwater depth in the contaminated area during the extraction process and the groundwater depth before the extraction, in meters; It is the hydraulic adjustment partial coefficient that affects the extraction section length adjustment coefficient, in s; is the permeability coefficient of the soil in the contaminated area, in m / s; is the length of the contaminated area, in meters; is the length of the injection part, in m;

[0013] If the length adjustment coefficient of the extraction section is calculated according to formula (1): If it is less than 1.0 m, then the length adjustment coefficient of the extraction part in equation (2) is Equal to 1.0 m.

[0014] As a preferred example, the The value range of is 1.5~2.5; The value range of is 3 to 8; The value range of is 0.8~1.2; The value range is 0.1~0.3.

[0015] As a preferred example, the injection well is located above the contaminated area and below the groundwater level; the extraction well is located below the contaminated area; and the injection well and the extraction well are parallel to the direction of groundwater flow.

[0016] In another aspect, the present invention provides a method for remediating groundwater, the method comprising:

[0017] S1. Through the horizontal directional drilling construction process, the injection well is drilled above the contaminated area, and the extraction well is drilled below the contaminated area;

[0018] S2. Install the treatment device and injection pump on the ground; install the extraction pump in the extraction well;

[0019] S3, start the injection pump and the extraction pump to allow the contaminated groundwater in the contaminated area to flow downward into the extraction well;

[0020] S4. Use an extraction pump to extract the contaminated groundwater from the extraction well and transport it to the treatment device, and keep the groundwater level in the contaminated area 0.95 lower than the water level before restoration. ~1.05 ;in, The difference between the groundwater depth in the contaminated area during the extraction process and the groundwater depth before the extraction, in meters;

[0021] S5. Use treatment equipment to repair polluted groundwater to reduce the concentration of pollutants in groundwater and meet the environmental quality requirements for groundwater reinjection;

[0022] S6. Use an injection pump to transport the repaired groundwater to the injection well. The groundwater flows from the injection well into the formation, forming a vertical hydraulic circulation in the polluted area, thereby achieving the repair of the polluted groundwater.

[0023] As a preferred example, in step S1, one injection well and one extraction well constitute an extraction work unit; multiple groups of extraction work units are arranged to cover the entire contaminated area.

[0024] As a preferred example, the multiple groups of pumping and injection working units work simultaneously; the distance between two adjacent groups of pumping and injection working units is 15 to 30 m.

[0025] Compared with the prior art, the groundwater remediation device and remediation method of the present invention can effectively expand the scope of remediation and improve the remediation efficiency. The remediation device of the present invention includes a horizontally arranged injection well, a horizontally arranged extraction well, a treatment device, an injection pump and an extraction pump. The injection well is located above the extraction well, and the contaminated area is located between the injection well and the extraction well. The present invention adopts a horizontal circulation well to promote the vertical mixing of groundwater, increase the contact area between the pollutant and the treatment agent, and thus improve the remediation efficiency. The present invention can adapt to different geological conditions and pollutant characteristics, and can be easily combined with other remediation technologies to form a comprehensive treatment plan. The present invention can design corresponding treatment plans for aquifers of different depths and different properties. It also has good applicability for sites with complex geological structures. At the same time, the present invention can be implemented under buildings, and can achieve the remediation of contaminated groundwater in production enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic diagram of the structure of a device according to an embodiment of the present invention;

[0027] Figure 2is a schematic structural diagram of an injection well in an embodiment of the present invention;

[0028] Figure 3 is a schematic structural diagram of an extraction well in an embodiment of the present invention;

[0029] Figure 4 This is the curve of vinyl chloride concentration changes under the traditional circulation well repair mode;

[0030] Figure 5 It is a curve diagram of vinyl chloride concentration variation in the horizontal circulation well repair mode of the present invention.

[0031] The figure includes: injection well 1, first connection part 11, injection part 12, first sieve hole 121, extraction well 2, second connection part 21, extraction part 22, second sieve hole 221, treatment device 3, injection pump 4, extraction pump 5, and contaminated area 6. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings.

[0033] like Figure 1 As shown, a contaminated groundwater remediation device according to an embodiment of the present invention comprises a horizontally arranged injection well 1, a horizontally arranged extraction well 2, a treatment device 3, an injection pump 4 and an extraction pump 5. The injection well 1 is located above the extraction well 2. The extraction pump 5 is located in the extraction well 2, and the extraction pump 5 is connected to the water inlet end of the treatment device 3, and the extraction pump 5 is used to transport the contaminated groundwater in the extraction well 2 to the treatment device 3. The injection pump 4 is connected to the water outlet end of the treatment device 3, and the injection pump 4 is used to inject the groundwater repaired by the treatment device 3 into the injection well 1.

[0034] The treatment device 3 is used to treat the contaminated groundwater according to the type of pollutants, and to repair the contaminated groundwater to water that meets the quality standards when it is reinjected into the formation, for example, by using a physical, chemical or biological treatment device. The treatment device 3 is an existing device. The injection pump 4 is used to inject the groundwater repaired by the treatment device 3 into the injection well 1. The repaired groundwater is injected into the formation through the injection well 1.

[0035] When the contaminated groundwater remediation device of the above embodiment is working, the injection pump 4 and the extraction pump 5 are turned on. The contaminated groundwater in the contaminated area 6 flows downward into the extraction well 2; the extraction pump 5 located in the extraction well 2 extracts the contaminated groundwater to the treatment device 3; the treatment device 3 remediates and treats the contaminated groundwater to make it meet the quality standards when it is reinjected into the formation; the injection pump 4 transports the remediated groundwater to the injection well 1, and the remediated groundwater flows from the injection well 1 into the formation.

[0036] The contaminated groundwater remediation device of this embodiment extracts contaminated groundwater, remediates it through the treatment device 3, and then injects it into the ground. The groundwater circulates between the contaminated area 6, the extraction well 2, the treatment device 3, and the injection well 1 to achieve the remediation of the contaminated groundwater. This helps to control and slow down the spread of pollutants in the groundwater. The remediation-treated groundwater is re-injected into the ground, which helps to gradually restore the groundwater quality of the contaminated area 6.

[0037] In the contaminated groundwater remediation device of the above embodiment, the injection well 1 and the extraction well 2 are both arranged horizontally, the injection well 1 is located above the extraction well 2, and the contaminated area 6 is located between the injection well 1 and the extraction well 2. The injection well 1 and the extraction well 2 form a horizontal circulation well. Compared with the traditional vertical circulation well, the injection well 1 and the extraction well 2 cross the entire contaminated area groundwater contamination plume range, have the advantage of a larger contact area with the contaminated plume, and a faster groundwater circulation rate, thereby achieving the effect of accelerating the pollution removal rate.

[0038] This embodiment uses a horizontal circulation well, which can greatly increase the repair efficiency. The traditional vertical circulation well uses a pumping-treatment-reinjection system to accelerate the hydraulic circulation within the circulation well by pumping water in the pumping well and lateral recharge. The pumping rate mainly depends on the water level difference between the pumping well and the surrounding groundwater for hydraulic circulation. The horizontal circulation well in this embodiment pumps water from the bottom and recharges from the top. Compared with the traditional vertical circulation well, the head pressure difference is greater and the hydraulic circulation speed is faster.

[0039] Preferably, Figure 2 As shown, the injection well 1 includes a first connecting portion 11 and an injection portion 12 which are connected and communicated with each other, and a first sieve hole 121 is provided on the wall of the injection portion 12. Figure 3 As shown, the extraction well 2 includes a second connecting portion 21 and an extraction portion 22 which are connected and communicated with each other, and a second sieve hole 221 is provided on the pipe wall of the extraction portion 22. The groundwater after being repaired and treated by the treatment device 3 flows out from the first sieve hole 121 on the pipe wall of the injection portion 12 and enters the underground soil layer. The groundwater flowing downward from the contaminated area 6 passes through the second sieve hole 221 of the extraction portion 22 and flows into the extraction well 2.

[0040] Preferably, the first sieve holes 121 are evenly distributed on the tube wall of the injection part 12, and two adjacent rows of first sieve holes 121 are staggered. The staggered first sieve holes 121 increase the contact area with the soil layer, increase the injection radius, and thus increase the water injection amount. The second sieve holes 221 are evenly distributed on the tube wall of the extraction part 22, and two adjacent rows of second sieve holes 221 are staggered. The staggered second sieve holes 221 increase the contact area with the soil layer, increase the water extraction radius, and thus increase the water extraction amount.

[0041] Preferably, the injection well 1 is located above the contaminated area 6 and below the groundwater level. This can ensure that the repaired groundwater does not carry air when it infiltrates and replenishes the groundwater, thereby reducing the permeability of the soil layer after the gas enters the aquifer, thereby reducing the remediation efficiency. At the same time, this can also prevent the contaminated groundwater from flowing in the strata above the groundwater level, thereby causing secondary pollution to the layer of soil. The extraction well 2 is located below the contaminated area 6. The contaminated area 6 is located between the injection well 1 and the extraction well 2. The injection well 1 and the extraction well 2 are parallel to the direction of groundwater flow. Usually, the length of the contaminated plume in the contaminated area along the groundwater flow direction is greater than the length perpendicular to the groundwater flow direction. Therefore, setting the injection well 1 and the extraction well 2 to be parallel to the groundwater flow direction can effectively capture organic pollutants within the groundwater pollution range.

[0042] Preferably, the length of the injection portion 12 is 0.5 to 0.8 times the length of the contaminated area, where the length of the contaminated area is the distance of the contaminated groundwater along the groundwater flow direction. If the length of the injection portion 12 is too long, for example, greater than the length of the contaminated area 6, then when the extraction rate of the extraction pump 5 is inappropriate, the range of pollutants in the contaminated area will be expanded.

[0043] Preferably, the length of the extraction portion 22 is According to formula (1) and formula (2), it is calculated as follows:

[0044] Formula (1)

[0045] Formula (2)

[0046] In the formula, is the length adjustment coefficient of the extraction section 22, in m; The spatial adjustment partial coefficient affecting the length adjustment coefficient of the extraction portion 22 is dimensionless; is the vertical distance between the injection part 12 and the extraction part 22, in m; It is the head adjustment partial coefficient that affects the length adjustment coefficient of the extraction section 22, dimensionless; The difference between the groundwater depth in the contaminated area during the extraction process and the groundwater depth before the extraction, in meters; The hydraulic adjustment partial coefficient affecting the length adjustment coefficient of the extraction section 22, in s; is the permeability coefficient of the soil in the contaminated area, in m / s; is the length of the contaminated area, in meters; is the length of the injection portion 12, in m. Preferably, The value range of is 1.5~2.5; The value range of is 3 to 8; The value range of is 0.8~1.2; The value range is 0.1~0.3.

[0047] If the length adjustment coefficient of the extraction section 22 is calculated according to formula (1): is less than 1.0 m, then the length adjustment coefficient of the extraction section 22 in equation (2) is =1.0 m. Only when the length adjustment coefficient of the extraction part 22 has a certain length can the extraction part 22 effectively capture the polluted groundwater, that is, the polluted groundwater will not flow to a larger pollution range. Therefore, the minimum length adjustment coefficient of the extraction part 22 is set to 1.0 m. If the length adjustment coefficient of the extraction part 22 is calculated according to formula (1), If it is greater than or equal to 1.0 m, the length adjustment coefficient of the extraction portion 22 in equation (2) is equal to the length adjustment coefficient of the extraction portion 22 calculated in equation (1).

[0048] The preferred embodiment of the present invention considers the influence of factors such as the vertical distance between the injection part 12 and the extraction part 22, the depth of groundwater in the contaminated area during the extraction process, and the permeability coefficient of the soil layer on the groundwater extraction efficiency and extraction range, and calculates the length of the extraction part 22 through equations (1) and (2). This can significantly increase the capture range of contaminated groundwater in the direction perpendicular to the groundwater flow, and effectively reduce the disturbance range along the groundwater flow direction, thereby avoiding the diffusion of pollutants.

[0049] In the above-mentioned device, only the treatment device 3 and the injection pump 4 are arranged on the ground, which occupies a small area. In the process of remediating contaminated groundwater with traditional vertical circulation wells, for large-scale remediation of contaminated groundwater, it is necessary to build multiple vertical wells and ground pipelines from the ground, while the horizontal circulation wells used in the embodiment of the present invention have the characteristics of large contact range with the contaminated plume and large head pressure difference, so the number of construction is small, which can achieve the purpose of increasing the disposal range. At the same time, the well construction area of ​​the horizontal circulation well in the embodiment of the present invention can usually be set to the same parallel orientation. Traditional circulation well remediation technology requires the establishment of a large number of vertical wells and surface pipelines on the surface, while the construction of the horizontal circulation well in the embodiment of the present invention is not affected by the surface construction, and the length of the injection part 12 can be flexibly set according to the surface production facilities, terrain and other conditions. For example, the length of the injection part 12 is 0.5 to 0.8 times the length of the contaminated area, and a good pollutant removal effect in groundwater can be obtained.

[0050] Using the repair device of the above embodiment or preferred example, the embodiment of the present invention also provides a method for repairing contaminated groundwater, comprising:

[0051] S1. Through the horizontal directional drilling construction process, the injection well 1 is drilled above the contaminated area 6, and the extraction well 2 is drilled below the contaminated area 6.

[0052] S2, installing the processing device 3 and the injection pump 4 on the ground; installing the extraction pump 5 in the extraction well 2.

[0053] S3, start the injection pump 4 and the extraction pump 5 to allow the contaminated groundwater in the contaminated area 6 to flow downward into the extraction well 2.

[0054] S4, use the extraction pump 5 to extract the contaminated groundwater from the extraction well 2, transport it to the treatment device 3, and keep the groundwater level in the contaminated area 6 0.95 lower than the water level before restoration ~1.05 ; It is the difference between the groundwater depth in the contaminated area during the extraction process and the groundwater depth before extraction, in meters. By controlling the groundwater level in the remediation area during the remediation process, the amount of pumped water and injected water can be effectively controlled, and the groundwater circulation efficiency will not be reduced due to the exposure of injection well 1 to the soil aeration zone.

[0055] S5, using the treatment device 3 to repair the contaminated groundwater, so that the concentration of pollutants in the groundwater is reduced to meet the environmental quality requirements of groundwater reinjection;

[0056] S6. The injection pump 4 is used to transport the repaired groundwater to the injection well 1. The groundwater flows from the injection well 1 into the stratum, forming a vertical hydraulic circulation in the contaminated area 6, thereby achieving the repair of the contaminated groundwater.

[0057] In the above method, when the injection pump 4 and the extraction pump 5 are both in the on state, the contaminated groundwater circulates between the injection well 1, the extraction well 2, the extraction pump 5, the treatment device 3, and the injection pump 4. The treatment device 3 remediates the contaminated groundwater into groundwater that meets the quality standards when it is reinjected into the formation, and then reinjects it into the formation. The extraction well 2 continuously extracts groundwater. The injection well 1 continuously injects the groundwater that has been remediated and treated by the treatment device 3 into the formation to meet the working conditions of the extraction well 2.

[0058] Preferably, in step S1, an injection well 1 and an extraction well 2 form an extraction work unit; multiple groups of extraction work units are arranged to cover the entire contaminated area. For a large contaminated area, multiple groups of extraction work units are arranged to achieve the remediation of contaminated groundwater in the entire contaminated area. Preferably, multiple groups of extraction work units work simultaneously; the distance between two adjacent groups of extraction work units is 15 to 30 m.

[0059] In the method of this embodiment, the horizontal circulation well can be constructed from one side to the other by horizontal directional drilling, and the injection well 1 and the extraction well 2 can be directly built under the structure, so as to achieve the purpose of repairing the contaminated groundwater without destroying the original structure. This embodiment does not require the establishment of repair facilities directly above, and is more suitable for operating scenarios such as in-production enterprises, contaminated plots where structures cannot be removed, and under contaminated roads. Compared with traditional treatment methods that require a large amount of surface infrastructure, the repair method of this embodiment can complete most of the work underground, reducing the demand for surface space and related environmental impacts.

[0060] The remediation method of this embodiment controls the direction of groundwater flow, and the horizontal circulation well can slow down or prevent the spread of pollutants to uncontaminated areas. The direction of groundwater flow is controlled by lowering the groundwater level in the contaminated area through horizontally arranged extraction wells, and then continuously injecting the repaired groundwater into the contaminated area through injection wells, thereby forming a vertical hydraulic cycle. The horizontal circulation well composed of injection well 1 and extraction well 2 pumps water at the bottom of the contaminated area, resulting in a greater head pressure difference in the water level within the contaminated area than in the traditional vertical circulation well, causing the contaminated groundwater to gather more quickly within the extraction well, and better preventing the spread of pollutants.

[0061] This embodiment uses a horizontal circulation well, which can be flexibly adjusted according to different geological conditions and pollutant types, including the ability to flexibly change the depth and length of the well. Since the injection well 1 and the extraction well 2 in this embodiment are both horizontal wells, through horizontal directional drilling construction, the well depth and well position can be changed by back-pulling means. The vertical well used in the traditional method requires the establishment of a borehole first, and once the construction is completed, it is difficult to move the position and change the depth.

[0062] In addition, the repair device and the repair method of this embodiment are also applicable to non-aqueous phase fluids. This embodiment adopts a horizontal circulation well, and forms a groundwater circulation in a vertical direction by constructing injection wells and pumping wells above and below the pollution plume in the vertical direction. Non-aqueous phase fluids can be effectively removed during the groundwater circulation process. The groundwater extracted from the horizontal circulation well used in this embodiment is vertical groundwater, which can better capture non-aqueous phase pollutants. In traditional circulation well technology, the groundwater extracted is lateral groundwater. During the extraction process, light water phase pollutants will drop as the water level drops, and heavy water phase pollutants sink above the aquiclude. It is necessary to continuously adjust the pumping position of the pump to extract the non-aqueous phase liquid.

[0063] An embodiment and a comparative example are given below.

[0064] The groundwater in a contaminated area contains vinyl chloride pollutants, with a maximum concentration of 1.5 mg / L and a contamination range of about 600 m 2, 5 m deep. Along the groundwater flow direction, the contaminated area is 30 m long (horizontally, along the groundwater flow direction) and 20 m wide (horizontally and perpendicular to the groundwater flow direction). The average permeability coefficient of the site soil is 3.5×10 -7 m / s. The groundwater depth is 0.6 m. The traditional vertical circulation well technology and the horizontal circulation well technology of the present invention are used for simulation calculation to obtain the removal effect of pollutants by different circulation wells.

[0065] The layout of the traditional vertical circulation wells is as follows: 12 injection wells are set on the pollutant boundary range in the plane range of the pollution plume, and 8 pumping wells are set in the middle range of the pollution plume for pumping water. The diameter of the injection well is 110 mm, the depth is 6 m, the sieve hole diameter is 3 mm, and the hole density is 6 mesh. The diameter of the pumping well is 110 mm, the depth is 6 m, the sieve hole diameter is 3 mm, and the hole density is 6 mesh.

[0066] The horizontal circulation well of the present invention is: one injection well and one extraction well are arranged, that is, one extraction work unit is arranged. The injection well is located at a depth of 0.4 m from the groundwater surface. Based on the groundwater burial depth of 0.6 m, the injection well burial depth is 1.0 m. The extraction well is located at a depth of 0.5 m directly below the pollution plume range. Based on the pollution area depth of 5 m, the extraction well burial depth is 5.5 m. The distance between the injection well and the extraction well is 4.5 m. The extraction work unit is arranged on the central axis on the pollution plume plane in the direction perpendicular to the groundwater flow.

[0067] The diameter of the water injection well is 110 mm, the aperture of the first sieve hole 121 is 3 mm, and the hole density is 6 meshes. In this embodiment, the length of the injection part of the water injection well is 0.7 times the length of the contaminated area, so the length of the injection part of the water injection well is 21 m.

[0068] The diameter of the extraction well is 110 mm, the aperture of the second sieve hole 221 is 3 mm, and the hole density is 6 meshes. The length of the extraction section is calculated according to equations (1) and (2). Let the difference between the groundwater depth in the contaminated area during the extraction and the groundwater depth before the extraction be The value is 0.2 m. The value is 2.0. The value is 5. If the value is 1.0, the length of the extraction section 22 =2×30-21+2.0×4.5-5×0.2+1.0×lg(3.5×10 -7 ) =40.54 m. In order to facilitate construction, the extraction length of the extraction well is taken as an integer of 41 m.

[0069] The concentration of vinyl chloride and pollutants were calculated using the Groundwater Modeling System simulation software. When the circulation well was running for 30 days, the traditional vertical circulation well repair mode was used. Figure 4 As shown in the figure, the maximum concentration of vinyl chloride was reduced to 0.4 mg / L, and the reduction rate of vinyl chloride concentration was 73.3%. Figure 4 In the horizontal well repair mode of the present invention, the horizontal axis represents time, unit: day; the vertical axis represents vinyl chloride concentration, unit: mg / L. Figure 5 As shown in the figure, the maximum concentration of vinyl chloride was reduced to 0.2 mg / L, and the reduction rate of vinyl chloride concentration was 86.7%. Figure 5 In the table, the horizontal axis represents time in days, and the vertical axis represents vinyl chloride concentration in mg / L. Figure 4 and Figure 5 It can be seen that: when the system runs for the same time, the pollutant removal rate of the horizontal circulation well using the present invention is higher than that of the traditional vertical circulation well.

[0070] In addition, the number of traditional vertical circulation wells used in the comparative example is 20, and the total length of the wells is 120m; while the embodiment uses one pumping and injection working unit, and the well length is 62m, which is only 51.67% of the well length of the comparative example. Therefore, the present invention can significantly reduce the well length, reduce the repair equipment, and reduce the construction cost.

[0071] The basic principles, main features and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above specific embodiments, and the descriptions in the above specific embodiments and 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, and these changes and improvements all fall within the scope of the present invention claimed for protection.

Claims

1. A contaminated groundwater remediation device, characterized in that: The device comprises a horizontally arranged injection well (1), a horizontally arranged extraction well (2), a processing device (3), an injection pump (4) and an extraction pump (5), The injection well (1) is located above the extraction well (2); the extraction pump (5) is located in the extraction well (2), the extraction pump (5) is connected to the water inlet of the treatment device (3), and the extraction pump (5) is used to transport the contaminated groundwater in the extraction well (2) to the treatment device (3); the injection pump (4) is connected to the water outlet of the treatment device (3), and the injection pump (4) is used to inject the groundwater repaired by the treatment device (3) into the injection well (1); The injection well (1) comprises a first connecting portion (11) and an injection portion (12) which are connected and communicated with each other, and a first sieve hole (121) is provided on the pipe wall of the injection portion (12); the extraction well (2) comprises a second connecting portion (21) and an extraction portion (22) which are connected and communicated with each other, and a second sieve hole (221) is provided on the pipe wall of the extraction portion (22); The length of the extraction portion (22) According to formula (1) and formula (2), it is calculated as follows: Formula (1) Formula (2) In the formula, is the length adjustment coefficient of the extraction section (22), in m; is the spatial adjustment partial coefficient affecting the length adjustment coefficient of the extraction portion (22), dimensionless; is the vertical distance between the injection part (12) and the extraction part (22), in meters; The head adjustment partial coefficient affecting the length adjustment coefficient of the extraction section (22), dimensionless; The difference between the groundwater depth in the contaminated area during the extraction process and the groundwater depth before the extraction, in meters; is the hydraulic adjustment partial coefficient affecting the length adjustment coefficient of the extraction section (22), in s; is the permeability coefficient of the soil in the contaminated area, in m / s; is the length of the contaminated area, in meters; is the length of the injection portion (12), in m; If the length adjustment coefficient of the extraction part (22) is calculated according to formula (1): If it is less than 1.0 m, the length adjustment coefficient of the extraction part (22) in equation (2) is Equal to 1.0 m.

2. The contaminated groundwater remediation device according to claim 1, characterized in that: The first sieve holes (121) are evenly distributed on the tube wall of the injection portion (12), and two adjacent rows of first sieve holes (121) are arranged in a staggered manner; the second sieve holes (221) are evenly distributed on the tube wall of the extraction portion (22), and two adjacent rows of second sieve holes (221) are arranged in a staggered manner.

3. The contaminated groundwater remediation device according to claim 1, characterized in that: The length of the injection portion (12) is 0.5 to 0.8 times the length of the contaminated area, and the length of the contaminated area is the distance of the contaminated groundwater along the direction of groundwater flow.

4. The contaminated groundwater remediation device according to claim 1, characterized in that: Said The value range of is 1.5~2.5; The value range of is 3 to 8; The value range of is 0.8~1.2; The value range is 0.1~0.

3.

5. The contaminated groundwater remediation device according to claim 1, characterized in that: The injection well (1) is located above the contaminated area (6) and below the groundwater level; the extraction well (2) is located below the contaminated area (6); the injection well (1) and the extraction well (2) are oriented parallel to the groundwater flow direction.

6. A method for repairing groundwater using the contaminated groundwater repair device according to any one of claims 1 to 5, characterized in that: The method comprises: S1. Using a horizontal directional drilling process, the injection well (1) is drilled above the contaminated area (6), and the extraction well (2) is drilled below the contaminated area (6); S2, installing a treatment device (3) and an injection pump (4) on the ground; installing an extraction pump (5) in the extraction well (2); S3, turning on the injection pump (4) and the extraction pump (5) to allow the contaminated groundwater in the contaminated area (6) to flow downward into the extraction well (2); S4. Use the extraction pump (5) to extract the contaminated groundwater from the extraction well (2) and transport it to the treatment device (3), and keep the groundwater level in the contaminated area (6) 0.95 lower than the water level before the restoration. ~1.05 ;in, The difference between the groundwater depth in the contaminated area during the extraction process and the groundwater depth before the extraction, in meters; S5. Using the treatment device (3) to repair the contaminated groundwater, so that the concentration of pollutants in the groundwater is reduced and the environmental quality requirements for groundwater reinjection are met; S6. Using an injection pump (4), the repaired groundwater is transported to the injection well (1). The groundwater flows from the injection well (1) into the stratum, forming a vertical hydraulic circulation in the contaminated area (6), thereby achieving the repair of the contaminated groundwater.

7. The method for repairing groundwater according to claim 6, characterized in that: In step S1, an injection well (1) and an extraction well (2) form an extraction work unit; multiple groups of extraction work units are arranged to cover the entire contaminated area.

8. The method for repairing groundwater according to claim 7, characterized in that: The multiple groups of pumping and injection working units work simultaneously; the distance between two adjacent groups of pumping and injection working units is 15 to 30 m.

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