A heavy metal pollutant composite treatment circulating well body structure and circulating well

Abstract

The application provides a heavy metal pollutant composite treatment circulating well body structure and a circulating well, which comprises an outer well pipe and an inner well pipe sleeved in the outer well pipe, the bottom of the outer well pipe and the bottom of the inner well pipe are both sealing structures, an annular cavity is formed between the outer side wall of the inner well pipe and the outer well pipe, a partition plate is arranged in the annular cavity and the annular cavity is divided into an annular upper cavity and an annular lower cavity which are not communicated with each other, a bottom cavity communicated with the annular lower cavity is formed between the bottom of the inner well pipe and the bottom of the outer well pipe, a permeation wall is arranged at the inner wall of the inner well pipe, the inner well pipe section corresponding to the permeation wall is a water filter pipe, the inner well pipe is communicated with the annular upper cavity through a water pump, the outer well pipe section corresponding to the annular upper cavity has a water filter pipe section, and the outer well pipe section corresponding to the annular lower cavity also has a water filter pipe section. The application has small environmental disturbance, significantly improves the treatment efficiency, and solves the problems of large excavation of a polluted site, long repair time and difficulty in cleaning or replacing the permeation wall in the prior art.

Description

Technical Field

[0001] This invention relates to the field of groundwater pollution remediation technology in the environmental protection field, and particularly to a well structure and circulation well for composite treatment of heavy metal pollutants. Background Technology

[0002] Improper disposal of various pollutants, improper discharge of urban wastewater, and overuse of agricultural chemicals can easily lead to serious pollution of groundwater and soil, affecting people's lives and health.

[0003] Currently, the commonly used remediation technologies in China for removing pollutants from groundwater and soil mainly include extraction and treatment technology, groundwater aeration technology, permeable reactive barrier technology, physical remediation technology, chemical remediation technology, and bioremediation technology. Each remediation technology is suitable for treating certain pollutants, but each also has its limitations.

[0004] Chinese patent document CN212102323U discloses a device for remediating groundwater using coated nano-zero-valent iron, comprising a well system, an extraction system, and an aeration system. The well system includes a well chamber and a well body. The well body, from the outside in, comprises a quartz sand layer, a mesh layer, an aquifer, another mesh layer, a permeable reactive layer, and another mesh layer. The permeable reactive layer consists of a porous medium and coated nano-zero-valent iron particles uniformly distributed within the porous medium. This utility model patent combines permeable reactive wall technology and circulating well technology. It uses the negative and positive pressure generated by cross-volume extraction and aeration to treat the water in the well, increasing the effective area for groundwater treatment. However, the groundwater is not flowing, making it difficult for pollutants to enter the well, thus limiting the radius of influence. Furthermore, the permeable wall is not designed according to the distribution of pollutants, resulting in resource waste.

[0005] Chinese patent document CN104692531A discloses a groundwater heavy metal pollution remediation device, mainly comprising: a pumping system, a water distribution system, an adsorption reaction zone, a phytoremediation zone, a rapid infiltration zone, and a monitoring system. The adsorption reaction zone is filled with a medium that adsorbs heavy metals to achieve the effect of removing heavy metals from groundwater. The phytoremediation zone is planted with super-accumulating plants that absorb and enrich heavy metals, enhancing the removal effect. This technology organically combines physical, chemical, and phytoremediation techniques and can remediate various heavy metal pollutions such as As, Zn, Cd, Mn, Cu, Cr, and Pb. However, the target aquifer volume is limited, requiring the excavation of a certain area of ​​soil, which damages the original ecosystem. If the polluted groundwater is not thoroughly treated in the reaction zone, it can easily cause secondary soil pollution. Furthermore, this treatment device is greatly affected by the season, and construction can only be carried out during the season when the desired plants are growing well.

[0006] Chinese patent document CN100998987A discloses an electrokinetic remediation method for contaminated soil and groundwater. This method involves placing positive and negative electrodes at both ends of the contaminated soil and groundwater area, with a distance of 30-60 cm between the electrodes. A conductive buffer solution is added between the negative electrode and the soil / groundwater, forming a conductive zone with a conductive length of 10-30 cm. This zone controls the pH of the electrode area, maintaining low pH conditions in the soil and groundwater, with an electric field gradient of 1-5 V / cm. The anode electrode uses a silver electrode, an aluminum plate electrode, or an iron rod electrode. This invention controls the electric field potential by selecting appropriate electrode materials, shapes, and sizes, using an active metal as the anode for efficient remediation of contaminated soil and groundwater. While this patent provides an electrokinetic remediation method, the remediation area is limited, the remediation cost is relatively high, and it alters the chemical properties of the groundwater and soil. Summary of the Invention

[0007] Therefore, the purpose of this invention is to provide a well structure for a composite treatment circulating well for heavy metal pollutants, which minimizes environmental disturbance and significantly improves treatment efficiency during the effective treatment of groundwater. To achieve the above objective, the technical solution of this invention is as follows:

[0008] A composite treatment circulation well structure for heavy metal pollutants includes an outer well pipe and an inner well pipe sleeved inside the outer well pipe. The bottoms of both the outer and inner well pipes are sealed structures. An annular cavity is formed between the outer wall of the inner well pipe and the outer well pipe. A partition is provided in the annular cavity, and the partition divides the annular cavity into an upper annular cavity and a lower annular cavity that are not connected to each other.

[0009] The bottom of the inner well pipe and the bottom of the outer well pipe form a bottom cavity that communicates with the lower annular cavity. A permeable wall is provided on the inner wall of the inner well pipe. The inner well pipe section corresponding to the permeable wall is a water filter pipe. The inner well pipe is connected to the upper annular cavity through a water pump. The outer well pipe section corresponding to the upper annular cavity has a water filter pipe section. The outer well pipe section corresponding to the lower annular cavity also has a water filter pipe section.

[0010] Furthermore, the well body structure of the heavy metal pollutant composite treatment circulation well also includes a sludge removal device, which includes a sewage extraction device and a sludge removal pipe. One end of the sludge removal pipe is connected to the bottom cavity, and the other end of the sludge removal pipe is connected to the sewage extraction device.

[0011] Furthermore, a permeable wall support is installed inside the inner well pipe. The bottom periphery of the permeable wall support has an outward-facing tray for placing the permeable wall. The tray is 300-850mm wide and 30-50mm from the lower end of the inner well pipe. The inner well pipe section corresponding to the permeable wall is a filter pipe, and the height of the permeable wall and the filter pipe is 1500-2500mm, depending on the distribution of the contamination plume. The permeable wall support also has a guide plate with a notch. The inner wall of the inner well pipe has a protrusion that mates with the notch. The protrusion is slidably connected to the guide plate, allowing the permeable wall support to move up and down along the inner wall of the inner well pipe. The guide plate facilitates the installation or replacement of the permeable wall.

[0012] Furthermore, the well body structure of the heavy metal pollutant composite treatment circulation well also includes a permeable wall cover plate disposed inside the inner well pipe, and the permeable wall cover plate covers the permeable wall.

[0013] Furthermore, the cross-sectional shape of the outer well pipe and the inner well pipe is racetrack-shaped, or the cross-sectional shape of the outer well pipe and the inner well pipe is rectangular.

[0014] Furthermore, both the outer and inner well casings are made of stainless steel, with the outer well casing having a wall thickness of 6-13mm and the inner well casing having a wall thickness of 3-6mm. Both the outer and inner well casings are welded together.

[0015] The distance between the bottom of the outer well pipe and the bottom of the inner well pipe is 900-1100mm, and the annular width of the annular cavity is 100-300mm.

[0016] Furthermore, the external well casing includes, from bottom to top, a sedimentation pipe, a lower filter pipe, a solid pipe, an upper filter pipe, and a solid pipe; the length of the lower filter pipe is 1500-2500mm, the length of the upper filter pipe is 800-1500mm, and the upper and lower filter pipes are filter pipes with a trapezoidal slit structure, or the upper and lower filter pipes are filter pipes with a wire-wound structure;

[0017] The upper and lower filter pipes can adopt a trapezoidal slit structure, that is, a trapezoidal slit is processed on a steel plate and then welded into a well pipe structure. The slit width is determined according to the thickness of the aquifer particles. Alternatively, the upper and lower filter pipes can adopt a wire-wound structure, that is, a well pipe structure is formed by welding wires and vertical wires. The gap between the wires is determined according to the size of the aquifer particles.

[0018] Furthermore, the material of the permeable wall is selected from one or more of activated carbon, zero-valent iron, bentonite, zeolite, synthetic ion exchange resin and limestone.

[0019] According to another aspect of the present invention, a heavy metal pollutant composite treatment circulation well is provided, comprising a main circulation well and an auxiliary circulation well, wherein the main circulation well is provided with a well body structure for heavy metal pollutant composite treatment circulation well as described in any of the above technical solutions;

[0020] Multiple auxiliary circulation wells are provided on one side of the main circulation well. Electrodes are provided in any two of the auxiliary circulation wells. The auxiliary circulation well closer to the main circulation well is provided with a negative electrode, and the auxiliary circulation well farther away from the main circulation well is provided with a positive electrode. The negative electrode is connected to the cathode of the DC power supply, and the positive electrode is connected to the anode of the DC power supply.

[0021] or,

[0022] Multiple auxiliary circulation wells are provided on one side of the main circulation well. Electrodes are provided in any two of the auxiliary circulation wells. The auxiliary circulation well closer to the main circulation well is provided with a negative electrode, and the auxiliary circulation well farther away from the main circulation well is provided with a positive electrode. The negative electrode is connected to the cathode of the DC power supply, and the positive electrode is connected to the anode of the DC power supply.

[0023] On the other side of the main circulation well, multiple auxiliary circulation wells are also provided. Electrodes are provided in any two of the auxiliary circulation wells. The auxiliary circulation well closer to the main circulation well is provided with a negative electrode, and the auxiliary circulation well farther away from the main circulation well is provided with a positive electrode. The negative electrode is connected to the cathode of the DC power supply, and the positive electrode is connected to the anode of the DC power supply.

[0024] Furthermore, the top of the annular upper cavity is 400-600mm above the ground. The cross-section of the main circulation well is racetrack-shaped or rectangular. The depth of the main circulation well is 5-20m, the width is 1000-2000mm, and the length is 5-10m. The specific structural dimensions of the well can be determined according to the width and depth of the groundwater pollution plume.

[0025] The beneficial effects of this invention are:

[0026] The heavy metal pollutant composite treatment circulating well structure and circulating well of the present invention have relatively small environmental disturbances and significantly improve treatment efficiency during the effective treatment of groundwater; it solves the problems of large excavation area of ​​contaminated site, long remediation time and difficulty in cleaning or replacing permeable walls in the prior art.

[0027] The present invention has the following advantages:

[0028] 1. Maintain a balance between water injection and extraction to prevent excessive disturbance to the formation;

[0029] 2. By installing a permeable wall in the well, the excavation area of ​​the soil is reduced. Through the circulation of groundwater, pollutants are carried into the permeable wall for treatment more quickly, preventing the pollutant plume from flowing around.

[0030] 3. After the groundwater passes through the filter pipe of the circulating well, it enters the water storage ring. Some sediment and particles will sink to the bottom of the water storage ring and will not enter the permeable wall, reducing the chance of the permeable wall being blocked and extending the service life of the permeable wall.

[0031] 4. By using an electric field device to guide heavy metals away from soil particles and into groundwater, they flow into the circulation well, expanding the remediation radius of the circulation well and improving remediation efficiency.

[0032] 5. The permeable wall can be removed from the well for cleaning or replacement. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of a circulating well for the composite treatment of heavy metal pollutants according to an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram showing the distribution of the main well and auxiliary wells of the circulating well according to an embodiment of the present invention;

[0035] Explanation of reference numerals in the attached figures:

[0036] 1. Outer well casing; 2. Inner well casing; 3. Annular upper cavity; 4. Annular lower cavity; 5. Upper filter pipe section;

[0037] 6. Lower filter pipe section; 7. Permeable wall cover plate; 8. Tray; 9. Permeable wall; 10. Bottom cavity;

[0038] 11 Water pump; 12 Water pipe; 13 Manhole cover; 14 Sewage extraction device; 15 Dredging pipe; 16 DC power supply;

[0039] 17 Positive electrode; 18 Negative electrode; 19 Circulation well auxiliary well; 20 Contaminated area; 21 Groundwater level; 22 Surface; 23 Circulation well main well. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the following detailed description of the structure of the heavy metal pollutant composite treatment circulating well and the circulating well of this invention, in conjunction with the accompanying drawings and embodiments, is provided. It should be noted that, unless otherwise specified, the following embodiments and features can be combined with each other. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this invention.

[0041] Reference Figure 1 and Figure 2 The well body structure of a heavy metal pollutant composite treatment circulation well according to an embodiment of the present invention includes an outer well pipe 1 and an inner well pipe 2 sleeved inside the outer well pipe 1.

[0042] Both the outer well casing 1 and the inner well casing 2 have sealed bottoms. An annular cavity is formed between the outer wall of the inner well casing 2 and the outer well casing 1. A partition is installed in the annular cavity, which divides the annular cavity into an upper annular cavity 3 and a lower annular cavity 4 that are not connected to each other.

[0043] A bottom cavity 10, communicating with the annular lower cavity, is formed between the bottom of the inner well pipe 2 and the bottom of the outer well pipe 1. A permeable wall 9 is provided on the inner wall of the inner well pipe 2. The inner well pipe section corresponding to the permeable wall 9 is a filter pipe. The inner well pipe 2 is connected to the annular upper cavity 3 via a water pump 11. The outer well pipe section corresponding to the annular upper cavity 3 has a filter pipe section, and the outer well pipe section corresponding to the annular lower cavity 4 also has a filter pipe section.

[0044] Figure 1 In the middle, the outer well section corresponding to the annular upper cavity 3 has an upper water filter section 5, and the outer well section corresponding to the annular lower cavity 4 has a lower water filter section 6.

[0045] The bottom of the outer well casing 1 and the inner well casing 2 can be sealed with a base or plate to form a sealing structure.

[0046] The water pipe 12 of the water pump 11 is connected to the upper end of the annular upper cavity 3. The water pump 11 can be a submersible pump to pump the purified groundwater in the well into the annular upper cavity 3 (upper water storage ring). The submersible pump can be a high-lift water pump. When the water injection in the annular upper cavity 3 (upper water storage ring) is slow, the submersible pump can be used to pressurize and accelerate the injection of groundwater.

[0047] As a preferred embodiment, the well structure for the combined treatment of heavy metal pollutants also includes a sludge removal device. The sludge removal device includes a wastewater extraction device 14 and a sludge removal pipe 15. One end of the sludge removal pipe 15 is connected to the bottom cavity 10, and the other end of the sludge removal pipe 15 is connected to the wastewater extraction device 14. The wastewater extraction device 14 can be an air compressor or a water pump.

[0048] As a preferred embodiment, both the outer well casing 1 and the inner well casing 2 can be made of stainless steel, with the outer well casing 1 having a wall thickness of 6-13 mm and the inner well casing 2 having a wall thickness of 3-6 mm. This ensures sufficient well body strength, and that deformation of the well body structure does not affect the normal operation of the circulation well. The distance between the bottom of the outer well casing 1 and the bottom of the inner well casing 2 is 900-1100 mm, preferably 1000 mm; the annular width of the annular cavity is 100-300 mm.

[0049] The outer well casing 1 and the inner well casing 2 can be connected by a partition, which can be made of stainless steel and welded to the outer well casing 1 and the inner well casing 2. The inner well casing 2 can have a base. The partition divides the space formed by the inner and outer well casings, forming upper and lower water storage rings. Among them, the annular upper cavity 3 serves as the upper water storage ring, and the annular lower cavity 4 serves as the lower water storage ring. The tops of the outer well casing 1 and the inner well casing 2 can be sealed with a well cover 13.

[0050] The upper and lower water storage rings are temporary water storage devices, with a width of 100-300 mm. The lower end of the upper water storage ring has a filter pipe through which groundwater can be discharged into the formation. The lower water storage ring is a transitional water ring; groundwater enters the lower water storage ring through the lower filter pipe and then enters the permeable wall 9.

[0051] The lower water storage ring allows large particles and sediment generated in the groundwater to settle into the bottom cavity 10 (sedimentation tank), preventing them from entering the permeable wall 9 and reducing the chance of the permeable wall becoming clogged.

[0052] The top of the upper water storage ring can be 400-600mm above the ground, preferably 500mm. Purified groundwater is pumped into the upper water storage ring and injected into the formation through a filter pipe installed in the upper water storage ring. The upper water storage ring forms a long and narrow ring structure, easily creating a hydraulic gradient difference between the groundwater in the upper water storage ring and the corresponding formation of the upper filter pipe section, which is beneficial for groundwater injection into the formation. Of course, in other embodiments, the top of the upper water storage ring can be higher than 500mm above the ground; for example, the top of the upper water storage ring can be at least 500mm above the ground.

[0053] Optionally, both the outer well casing 1 and the inner well casing 2 can have a racetrack-shaped cross-section. That is, the two ends are semi-circular, and the middle is a rectangular structure. Alternatively, both the outer well casing 1 and the inner well casing 2 can have a rectangular cross-section.

[0054] A permeable wall support is installed inside the inner well pipe 2. The bottom periphery of the permeable wall support has an outward-facing tray 8 for placing the permeable wall 9. The tray 8 is 300-850mm wide and 30-50mm away from the lower end of the inner well pipe 2. The inner well pipe section corresponding to the permeable wall 9 is a filter pipe, and the height of the permeable wall 9 and the filter pipe is 1500-2500mm. The permeable wall support also has a guide plate with a notch. The inner wall of the inner well pipe 2 has a protrusion that mates with the notch. The protrusion is slidably connected to the guide plate, allowing the permeable wall support to move up and down along the inner wall of the inner well pipe 2. The protrusion and guide plate facilitate the installation or replacement of the permeable wall.

[0055] In this embodiment, the material of the permeable wall 9 is selected from one or more of the following: activated carbon, zero-valent iron, bentonite, zeolite, synthetic ion exchange resin, and limestone. One, two, or more of these materials may be selected.

[0056] An annular support can be installed inside the inner well pipe 2. The tray 8 of the annular support is also annular. The tray 8 is used to place the permeable wall 9. The bottom of the tray 8 is 30-50mm away from the bottom of the inner well pipe 2. The tray 8 is made of stainless steel and has a width of 300-850mm. The support height can be 1500-2500mm.

[0057] The support is used to place the permeable wall 9, which is made of a material medium, including activated carbon, zero-valent iron, zeolite, synthetic ion exchange resin, and limestone, etc. The material medium can be placed between two grid layers.

[0058] Depending on the type and concentration of heavy metal pollutants, the permeable wall 9 can be made by selecting activated carbon, zero-valent iron, and bentonite in the optimal ratio.

[0059] The permeable wall 9 is placed on the support of the inner well pipe 2, and a permeable wall cover plate 7 is provided on the permeable wall 9. The permeable wall cover plate 7 covers the permeable wall 9. This allows the permeable wall 9 to be pulled out for cleaning or replacement.

[0060] The dredging device includes a sewage extraction device 14 and a dredging pipe 15. One end of the dredging pipe 15 is connected to the bottom cavity 10, and the other end of the dredging pipe 15 is connected to the sewage extraction device 14. The sewage extraction device 14 can be an air compressor, so the dredging device is the dredging pipe 15 connected to the air compressor. The dredging pipe 15 is made of seamless stainless steel pipe. The dredging pipe 15 extends into the main well, passes through the bottom plate of the inner well pipe, and connects to the bottom cavity 10 (sedimentation tank).

[0061] The sewage extraction device 14 can be fixed to the permeable wall cover plate 7 on the permeable wall 9. Of course, the sewage extraction device 14 can also be installed above the ground. The water pump 11 and its water pipe can also be fixed to the permeable wall cover plate 7, and the water pump 11 is also placed at the bottom end inside the inner well pipe 2.

[0062] Preferably, the external well casing 1 includes, from bottom to top, a sedimentation pipe, a lower filter pipe, a solid pipe, an upper filter pipe, and a solid pipe. The lower filter pipe is... Figure 1 The lower filter pipe section 6 is the upper filter pipe. Figure 1 Section 5 of the upper water filter pipe.

[0063] The length of the lower water filter pipe section 6 is 1500-2500mm; the length of the upper water filter pipe section 5 is 800-1500mm.

[0064] The upper and lower filter pipes can adopt a trapezoidal slit structure, that is, trapezoidal slits are machined on a steel plate and then welded into a well pipe structure, with the slit width determined according to the thickness of the aquifer particles; the upper and lower filter pipes can also adopt a wire-wound structure, that is, wires and vertical wires are welded into a well pipe structure, with the gap between the wires determined according to the size of the aquifer particles. Both of these designs can effectively reduce the probability of filter pipe blockage.

[0065] According to another aspect of the present invention, a heavy metal pollutant composite treatment circulation well is provided, including a main circulation well 23 and an auxiliary circulation well 19 (monitoring well), wherein the main circulation well 23 is provided with a well body structure for heavy metal pollutant composite treatment circulation well as described in any of the above technical solutions.

[0066] Multiple auxiliary circulation wells 19 are provided on one side of the main circulation well 23. Electrodes are provided in any two of the auxiliary circulation wells 19. The auxiliary circulation well 19 closer to the main circulation well 23 is provided with a negative electrode 18, and the auxiliary circulation well 19 farther away from the main circulation well 23 is provided with a positive electrode 17. The negative electrode 18 is connected to the cathode of the DC power supply 16, and the positive electrode 17 is connected to the anode of the DC power supply 16.

[0067] or,

[0068] Multiple auxiliary circulation wells 19 are provided on one side of the main circulation well 23. Electrodes are provided in any two of the auxiliary circulation wells 19. A negative electrode 18 is provided in the auxiliary circulation well 19 closer to the main circulation well 23, and a positive electrode 17 is provided in the auxiliary circulation well 19 farther away from the main circulation well 23. The negative electrode 18 is connected to the cathode of the DC power supply 16, and the positive electrode 17 is connected to the anode of the DC power supply 16.

[0069] On the other side of the main circulation well 23, multiple auxiliary circulation wells 19 are also provided. Electrodes are provided in any two of the auxiliary circulation wells 19. The auxiliary circulation well 19 closer to the main circulation well 23 is provided with a negative electrode 18, and the auxiliary circulation well 19 farther away from the main circulation well 23 is provided with a positive electrode 17. The negative electrode 18 is connected to the cathode of the DC power supply 16, and the positive electrode 17 is connected to the anode of the DC power supply 16. Figure 2 In the middle, multiple auxiliary circulation wells 19 are set on the left and right sides of the main circulation well 23.

[0070] Preferably, the upper water storage ring is 400-600mm above the ground, the cross-section of the main circulation well 23 is racetrack-shaped or rectangular, the depth of the main circulation well 23 is 5-20m, the width is 1000-2000mm, and the length is 5-10m. The specific structural dimensions of the well can be determined according to the width and depth of the groundwater pollution plume.

[0071] The top of the upper water storage ring is preferably 500mm above the ground surface; however, the top of the upper water storage ring can also be higher than 500mm, for example, at least 500mm above the ground surface. The purified groundwater is pumped into the upper water storage ring and injected into the formation through a filter pipe installed in the upper water storage ring. The upper water storage ring forms a long and narrow ring structure, and a hydraulic gradient difference is easily formed between the groundwater in the upper water storage ring and the corresponding formation of the upper filter pipe section, which is beneficial for groundwater injection into the formation.

[0072] The working principle of circulating well technology is as follows: By establishing a three-dimensional circulating flow field of water in the circulating well area, the circulating flow washes away and carries pollutants into the well. Physical, chemical, and biological techniques are used to remove pollutants from the water, thereby achieving groundwater remediation. A permeable wall is built in the circulating well, and an external electric field is applied to promote the detachment of heavy metal pollutants from the vadose zone and aquifer soil particles, allowing them to enter the groundwater and migrate towards the circulating well. When the heavy metal pollutants pass through the permeable wall, they are treated. The treated groundwater is then pumped to the upper reservoir ring (upper reservoir ring) and discharged into the formation through the upper reservoir ring.

[0073] like Figure 1 As shown, groundwater enters the annular lower cavity 4 (lower water storage ring) through the lower filter pipe section 6. Large particles of sand and gravel and the resulting sediment will sink into the sedimentation tank 10. After the groundwater fills the annular lower cavity 4 (lower water storage ring), it enters the permeable wall 9. In the permeable wall 9, the pollutants are purified by the permeable wall. The groundwater enters the main well and is pumped into the annular upper cavity 3 (upper water storage ring) by the water pump 11. The groundwater is injected into the formation through the upper filter pipe section 5, forming a three-dimensional circulation of groundwater. Figure 1 The area between the two wavy lines is the contaminated zone 20. The attached map label 21 is the groundwater level line, and the attached map label 22 is the ground surface.

[0074] To allow heavy metal ions to detach from soil particles and enter groundwater, an external electric field was installed. The anode and cathode electrode plates were placed in their respective auxiliary wells 19 (monitoring wells) of the circulation well, with the cathode electrode plate closer to the main circulation well. After approximately 8 hours of energization or until the current stabilized, the power was cut off, the electrode plates were removed, and the anode electrode plate was placed in the same monitoring well as the cathode electrode plate. The cathode electrode plate was then placed in a monitoring well closer to the main well. (Details follow...) Figure 2 As shown, the anode electrode plate is placed in the first monitoring well from the left (circulation well auxiliary well 19), and the cathode electrode plate is placed in the second monitoring well from the left. After energizing, the electrode plates are removed, the anode electrode plate is placed in the second monitoring well from the left, and the cathode electrode plate is placed in the third monitoring well from the left. Then, the power is turned on. The same sequence is used to place the electrodes and energize them in the circulation well on the other side of the main well. If multiple rows of circulation wells are set up, each row of circulation wells can be operated in this manner. Sensors can also be installed in the monitoring wells to monitor changes in the concentration of pollutants in the groundwater within the well. Monitoring wells can be set up in one row, or two rows or more depending on the distribution range of pollutants.

[0075] Figure 2 In the middle, the three auxiliary circulation wells 19 on the left side of the main circulation well 23 are monitoring well #1, monitoring well #2 and monitoring well #3, respectively; the three auxiliary circulation wells 19 on the right side of the main circulation well 23 are monitoring well #4, monitoring well #5 and monitoring well #6, respectively.

[0076] Anode electrode plate placed Figure 2 In monitoring well #1, place the cathode electrode plate into monitoring well #2. After energizing (approximately 8 hours or until the current stabilizes, then disconnect the power), remove the electrode plate. Place the anode electrode plate into monitoring well #2, and the cathode electrode plate into monitoring well #3, then reconnect the power. Repeat the same sequence for the circulating wells on the other side of the main well. For example, place the anode electrode plate into monitoring well #6 and the cathode electrode plate into monitoring well #5. After energizing, remove the electrode plates, place the anode electrode plate into monitoring well #5, and the cathode electrode plate into monitoring well #4, then reconnect the power. If multiple rows of circulating wells are installed, each row can be operated in the same manner.

[0077] The external electric field device may include a DC power supply 16, an ammeter, a cathode electrode 18, and an anode electrode 17. The cathode electrode 18 and anode electrode 17 may be made of ruthenium-iridium coated titanium mesh and graphite, respectively. For example: the anode electrode 17 may be made of ruthenium-iridium coated titanium mesh, and the cathode electrode 18 may be made of graphite; the cathode electrode 18 may be made of ruthenium-iridium coated titanium mesh, and the anode electrode 17 may be made of graphite; the cathode electrode 18 and anode electrode 17 may both be made of ruthenium-iridium coated titanium mesh; or the cathode electrode 18 and anode electrode 17 may both be made of graphite. Both the positive electrode 17 and the negative electrode 18 are electrically connected to the DC power supply 16, which may have a voltage of 30V.

[0078] The key technical points are as follows:

[0079] 1. Establish a three-dimensional circulating flow field of water in the circulating well area, and the circulating flow will flush and carry pollutants into the well;

[0080] 2. The permeable wall is built in the circulation well. The pollutants are removed by the three-dimensional water flow formed around the circulation well as it carries the pollutants through the permeable wall.

[0081] 3. In the monitoring wells designed in the areas where heavy metal pollutants are distributed, electrodes are inserted. An external electric field is used to cause heavy metal ions to detach from soil particles, enter the groundwater, and move towards the circulation well.

[0082] 4. A water-proof bottom plate is installed in the dual-well pipe structure, and a water storage ring is formed in the upper layer to separate it from the lower layer;

[0083] 5. The treated groundwater is pumped into the upper water storage ring.

[0084] 6. By pressurizing the water storage ring, the speed and depth of groundwater entering the strata are accelerated, thereby expanding the circulation radius;

[0085] 7. To maintain a balance between pumping and injection water, prevent excessive disturbance to the formation, and increase the influence radius of the circulating well.

[0086] 8. The lower groundwater enters the lower water storage ring through the filter pipe, where some particles will settle to prevent them from entering the permeable wall;

[0087] 9. A sedimentation tank is installed at the bottom, and the sediment is cleaned regularly.

[0088] The heavy metal pollutant composite treatment circulation well structure and circulation well of the above embodiments can significantly improve treatment efficiency, minimize environmental disturbance, accelerate remediation speed, and fully guarantee remediation efficiency through the combined use of multiple remediation technologies in the effective treatment of groundwater. It is also cost-effective, highly practical, and has great promotional value. It solves the problems of large excavation area of ​​contaminated site, long remediation time, and difficulty in cleaning or replacing permeable walls in the prior art.

[0089] The present invention has the following advantages:

[0090] 1. Maintain a balance between water injection and extraction to prevent excessive disturbance to the formation;

[0091] 2. By installing a permeable wall in the well, the excavation area of ​​the soil is reduced. Through the circulation of groundwater, pollutants are carried into the permeable wall for treatment more quickly, preventing the pollutant plume from flowing around.

[0092] 3. After the groundwater passes through the filter pipe of the circulating well, it enters the water storage ring. Some sediment and particles will sink to the bottom of the water storage ring and will not enter the permeable wall, reducing the chance of the permeable wall being blocked and extending the service life of the permeable wall.

[0093] 4. By using an electric field device to guide heavy metals away from soil particles and into groundwater, they flow into the circulation well, expanding the remediation radius of the circulation well and improving remediation efficiency.

[0094] 5. The permeable wall can be removed from the well for cleaning or replacement.

[0095] The above-described embodiments are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and all equivalent implementations or changes made without departing from the spirit of the present invention should be included within the protection scope of the present invention.

Claims

1. A heavy metal pollutant composite treatment circulating well, characterized in that, The application relates to a heavy metal pollutant composite treatment circulating well, which comprises a circulating well main well (23) and a circulating well auxiliary well (19), a heavy metal pollutant composite treatment circulating well body structure is arranged in the circulating well main well, the heavy metal pollutant composite treatment circulating well body structure comprises an outer well pipe (1) and an inner well pipe (2) sleeved in the outer well pipe (1), the bottom of the outer well pipe (1) and the inner well pipe (2) is a sealing structure, an annular cavity is formed between the outer side wall of the inner well pipe (2) and the outer well pipe (1), a partition plate is arranged in the annular cavity, and the partition plate divides the annular cavity into an annular upper cavity (3) and an annular lower cavity (4) which are not communicated with each other; the cross section shape of the outer well pipe (1) and the inner well pipe (2) is runway-shaped, that is, the two ends are semicircular, and the middle part is a rectangular structure; a bottom cavity (10) communicated with the annular lower cavity (4) is formed between the bottom of the inner well pipe (2) and the bottom of the outer well pipe (1), a permeation wall (9) is arranged at the inner wall of the inner well pipe (2), the inner well pipe section corresponding to the permeation wall (9) is a water filter pipe, the inner well pipe (2) is communicated with the annular upper cavity (3) through a water pump (11), the outer well pipe section corresponding to the annular upper cavity (3) has a water filter pipe section, and the outer well pipe section corresponding to the annular lower cavity (4) also has a water filter pipe section; a dredging device is further arranged, the dredging device comprises a sewage pumping device (14) and a dredging pipe (15), one end of the dredging pipe (15) is communicated with the bottom cavity (10), and the other end of the dredging pipe (15) is communicated with the sewage pumping device (14); a permeation wall support is arranged in the inner well pipe (2), the bottom end of the permeation wall support is provided with an outward tray (8), the tray (8) is used for placing the permeation wall (9), the width of the tray (8) is 300-850 mm, the tray (8) is 30-50 mm away from the lower end of the inner well pipe (2), the inner well pipe section corresponding to the permeation wall (9) is a water filter pipe, the height of the permeation wall (9) and the water filter pipe is 1500-2500 mm, the permeation wall support is further provided with a guide plate, the guide plate is provided with a notch, the inner side wall of the inner well pipe (2) is provided with a convex strip matched with the notch, the convex strip is slidably connected with the guide plate, so that the permeation wall support can move up and down along the inner wall of the inner well pipe (2); the outer well pipe (1) comprises a precipitation pipe, a lower water filter pipe, a solid pipe, an upper water filter pipe and a solid pipe from bottom to top; the length of the lower water filter pipe is 1500-2500 mm, the length of the upper water filter pipe is 800-1500 mm, the upper water filter pipe and the lower water filter pipe are water filter pipes adopting trapezoidal slot structures, or the upper water filter pipe and the lower water filter pipe are water filter pipes adopting wire winding structures. The circulating well main well is provided with a plurality of circulating well auxiliary wells (19) on one side, and electrodes are arranged in any two of the circulating well auxiliary wells (19), wherein a negative electrode (18) is arranged in the circulating well auxiliary well close to the circulating well main well, a positive electrode (17) is arranged in the circulating well auxiliary well away from the circulating well main well, the negative electrode (18) is connected to the cathode of a direct current power supply (16), and the positive electrode (17) is connected to the anode of the direct current power supply (16); The circulating well main well is provided with a plurality of circulating well auxiliary wells (19) on the other side, and electrodes are arranged in any two of the circulating well auxiliary wells (19), wherein a negative electrode (18) is arranged in the circulating well auxiliary well close to the circulating well main well, a positive electrode (17) is arranged in the circulating well auxiliary well away from the circulating well main well, the negative electrode (18) is connected to the cathode of a direct current power supply (16), and the positive electrode (17) is connected to the anode of the direct current power supply (16).

2. The heavy metal pollutant composite treatment cycled well of claim 1, wherein, A permeation wall cover plate (7) arranged in the inner well pipe (2) is further included, and the permeation wall cover plate (7) is arranged on the permeation wall (9).

3. The heavy metal pollutant composite treatment cycled well of claim 1, wherein, The outer well pipe (1) and the inner well pipe (2) are both made of stainless steel, the wall thickness of the outer well pipe (1) is 6-13 mm, the wall thickness of the inner well pipe (2) is 3-6 mm, and the outer well pipe (1) and the inner well pipe (2) are both formed by welding. The distance between the bottom of the outer well pipe (1) and the bottom of the inner well pipe (2) is 900-1100 mm, and the annular width of the annular cavity is 100-300 mm.

4. The heavy metal pollutant composite treatment cycled well of claim 1, wherein, The material of the permeation wall (9) is selected from one or more of activated carbon, zero-valent iron, bentonite, zeolite, synthetic ion exchange resin and limestone.

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