Reusable groundwater polluted single well repairing device

Abstract

The invention discloses a reusable groundwater polluted single well remediation device, and relates to the field of ecological environmental protection, the device comprises an outer well casing, a filter material cage and an inner well casing; the outer well pipe is provided with a permeable section and a non-permeable section to limit the depth of groundwater pollution remediation, and a filtering unit is used for intercepting large-particle substances in groundwater; pollutants are removed by filling the filter material cage with an adsorbent, the inner wall of the filter material cage is paved with geotechnical cloth to prevent loss of adsorbent particles, and different types of groundwater pollution can be repaired by selecting a specific adsorbent; the inner well pipe is used for collecting clean underground water, and a ring positioning device is arranged at the bottom and used for fixing the inner well pipe. When the adsorbent is saturated and loses efficacy, the filter material cage can be taken out and the adsorbent in the filter material cage is replaced to realize repeated utilization, so that the later operation and maintenance cost can be controlled. The single well repairing device has the advantages of being small in construction amount, moderate in treatment volume, easy and convenient to operate and maintain, low in cost and the like, and is particularly suitable for semi-centralized water supply in underdeveloped rural areas.

Description

Technical Field

[0001] The invention belongs to the field of ecological environmental protection, and in particular relates to a reusable groundwater contaminated single well repair device. Background Art

[0002] Groundwater pollution is a widespread problem worldwide. In my country, only 52.53% and 14.03% of the monitoring points in the Yangtze River and Yellow River basins meet the I~III water standards, and the area of ​​shallow groundwater exceeding the standard accounts for as high as 59.49% of the country. Groundwater pollution has become an important factor restricting the development and utilization of groundwater resources in my country. The research and development of groundwater pollution remediation technology is a hot spot and difficulty in the current ecological and environmental protection field.

[0003] Groundwater pollution remediation technologies can be roughly divided into two categories: in-situ and ex-situ remediation, mainly including extraction treatment technology, chemical remediation technology, electric remediation technology, multiphase extraction technology, microbial remediation technology, permeable reaction wall technology, etc. These remediation technologies can treat a large volume of groundwater, but there are problems such as high construction difficulty, large engineering volume, and high construction and operation and maintenance costs. They are usually suitable for centralized remediation of groundwater pollution on large-scale, high-economic-value projects.

[0004] However, in the vast rural areas of my country, due to low population density and underdeveloped economy, the above-mentioned repair technologies are often not applicable. In small-scale water supply scenarios, some decentralized treatment devices show better applicability, such as the currently more commonly used household water purifiers. However, the purchase cost of a commercial household water purifier is thousands of yuan, and the subsequent filter element replacement cost is hundreds of yuan each time. In addition, groundwater contains more soluble ion components, which has a large load on the filter element of a household water purifier, seriously affecting the service life of the filter element, resulting in frequent filter element replacement, which is not economically friendly to rural families. In many areas, water purifiers are abandoned after purchase.

[0005] Taking into account the disposal volume, economic feasibility and other issues, the semi-centralized single-well treatment method may be more suitable for underdeveloped rural areas. On the one hand, the flow of a single well is sufficient to supply daily water for dozens of households. On the other hand, the construction cost of repairing a single well is much lower than that of large-scale structures such as rural water plants or permeable reaction walls. By spreading the construction cost of a single well to water users, the economic pressure on residents can be further reduced.

[0006] Service life is another major challenge of groundwater contaminated single well remediation technology. Existing single well remediation technology usually fills the outer wall of the well pipe with fillers, and fixes pollutants in the groundwater by adsorption. When the filler reaches adsorption saturation, it will lose the ability to treat pollutants, and a new single well structure needs to be built. This defect makes the groundwater remediation single well a disposable consumable, which greatly limits the practical application of groundwater single well remediation technology. Therefore, it is necessary to develop a reusable groundwater contaminated single well remediation device. Summary of the invention

[0007] In view of the above problems, the present invention provides a low-cost, reusable groundwater contaminated single well repair device, which can realize the replacement of fillers in the repair well during use, and meet the repeated and continuous use of the repair well. The specific technical solution is as follows: A reusable groundwater contaminated single well repair device comprises, from outside to inside, an outer well pipe, a filter cage and an inner well pipe, wherein a plurality of filter cages are provided and stacked and sleeved between the inner well pipe and the outer well pipe; The outer well pipe comprises a lower outer well pipe permeable section and an upper outer well pipe impermeable section. The outer well pipe permeable section is provided with an outer well pipe water inlet hole on its wall to allow groundwater to pass through. When in use, a filter unit is provided on the outer side of the outer well pipe permeable section. The filter unit is filled with fine sand to block large particles in the groundwater. The filter cage is composed of a filter cage cover plate, a filter cage outer ring and a filter cage inner ring; the filter cage outer ring and the filter cage inner ring are both provided with filter cage water inlet holes; The inner well pipe is composed of, from top to bottom, a first watertight section of the inner well pipe, a water-permeable section of the inner well pipe, a second watertight section of the inner well pipe and a circular positioning device, and an inner well pipe water inlet hole is provided on the pipe wall of the water-permeable section of the inner well pipe to allow groundwater to pass through; The bottom of the first impermeable section of the inner well pipe is longer than the bottom of the impermeable section of the outer well pipe, so as to limit the flow path of groundwater and avoid the problem of low pollution treatment rate caused by preferential flow in the gaps of the filter cage stacking; Furthermore, the filter material filled in the filter cage includes an adsorbent or clay, wherein the water-permeable section of the outer well pipe is filled with the adsorbent to purify the groundwater quality, and the water-impermeable section of the outer well pipe is filled with clay to isolate water; The adsorbent should be a material with a large adsorption capacity for the target pollutants, cheap and easily available, and the adsorbent should be in granular form with a particle size larger than the aquifer sediment so that groundwater can passively flow into the filter cage; The filter cage cover includes a non-porous cover and a perforated cover. The non-porous cover is used to repair the top and bottom positions of a single well device, and the perforated cover is used for other positions except the top and bottom of the single well repair device. Geotextile is laid between the filter cage and the filter material.

[0008] Furthermore, the annular positioning device is composed of an inner annular ring, an outer annular ring and a connecting plate. The outer annular ring is connected and fixed to the inner annular ring by welding through three groups of connecting plates, and the inner annular ring is connected to the second watertight section of the inner well pipe by welding.

[0009] Furthermore, a plurality of screw holes are provided on the filter cage cover plate, the outer screw holes are connected and fixed to the outer ring of the filter cage, and the inner screw holes are connected and fixed to the inner ring of the filter cage.

[0010] Furthermore, the upper and lower inner sides of the filter cage outer ring and the filter cage inner ring are each provided with four nuts connected and fixed to the filter cage cover plate.

[0011] Furthermore, the outer well pipe and the inner well pipe have the same length, between 6-12m, and the bottom depth of the repair well should stay in the aquifer section with better water-richness. The length of the filter cage should be moderate, between 0.5-1m, to ensure that the filling amount of the adsorbent is increased as much as possible under the weight that can be installed manually, while being compatible with the height of the repair well. The impermeable section of the outer well pipe is longer than the burial depth of the groundwater level. The upper impermeable section of the outer well pipe is stacked with impermeable clay filter cages, and the lower permeable section is stacked with adsorbent filter cages to ensure that the filled adsorbent can contact the groundwater and avoid waste of adsorbent.

[0012] Furthermore, the inner diameter of the outer well pipe is 1 cm longer than the outer diameter of the outer ring of the filter cage, the outer diameter of the inner well pipe is 0.5 cm shorter than the inner diameter of the inner ring of the filter cage, and the diameter of the outer ring of the ring positioning device is consistent with the outer ring of the filter cage, ensuring that the sizes of each component of the single well repair device are easy to install.

[0013] The present invention also provides a method for installing and using the aforementioned reusable groundwater contaminated single well repair device, comprising the following steps: Step (1), detecting and determining the depth of the groundwater level, and determining the depth of the repair well, the depth range of the impermeable section and the permeable section of the outer well pipe, and the height of the filter cage according to the water level and the water-richness of the aquifer; Step (2), drilling a repair well with a drilling rig, winding yarn on the outside of an outer well pipe and arranging it in the repair well, and filling fine sand on the outside of the outer well pipe as a filtering unit of the single well repair device; Step (3), placing the inner well tube into the outer well tube, with the circular positioning device placed at the bottom; Step (4), assembling a plurality of filter cages, stacking and installing them one by one between the outer well pipe and the inner well pipe, placing a geotextile in the filter cages and filling them with an adsorbent or clay, the filter cages filled with adsorbents are stacked in the water-permeable section of the outer well pipe, and the filter cages filled with clay are stacked in the water-impermeable section of the outer well pipe, the top cover plate of the filter cage and the bottom cover plate of the filter cage are non-porous cover plates, and the other parts are all perforated cover plates; Step (5), connect a water pump to the top of the inner well pipe.

[0014] Furthermore, the method further includes step (6), when the adsorbent in the filter cage reaches adsorption saturation, the filter cages are taken out one by one, the adsorbent is replaced and then stacked again and loaded into the repaired single well, so as to achieve the purpose of reusing the single well repair device and reducing the operation and maintenance cost.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention achieves the effect of groundwater pollution restoration by filling a single well with an adsorbent. Compared with traditional in-situ restoration technology, the construction volume of the single well restoration construction is smaller and the construction cost is significantly reduced. A filtering unit is arranged on the outside of the outer well pipe and a geotextile is laid on the inside of the filter cage to filter large particles in the groundwater to prevent clogging of the adsorbent pores and ensure the normal operation of the single well restoration. The target depth of groundwater pollution restoration is limited by setting the range of the permeable section and the impermeable section. When the adsorbent in the filter cage is saturated and fails, the filter cage can be taken out and re-sunk into the well after the adsorbent is replaced, so as to achieve the purpose of reuse and significantly reduce the operation and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a schematic diagram of the components of the present invention; Figure 3 It is a structural schematic diagram of the filter cage of the present invention; Figure 4 It is a structural schematic diagram of the circular ring positioning device of the present invention; Figure 5 This is a demonstration of the groundwater pollution remediation effect in an embodiment of the present invention.

[0017] Reference numerals: 1. Outer well pipe; 11. Permeable section of outer well pipe; 12. Impermeable section of outer well pipe; 13. Water inlet of outer well pipe; 14. Filter unit; 2. Filter cage; 21. Filter cage cover; 2101. Cover with holes; 2102. Cover without holes; 22. Outer ring of filter cage; 23. Inner ring of filter cage; 24. Screw hole; 25. Nut; 26. Screw; 27. Water inlet of filter cage; 28. Adsorbent; 29. ​​Clay; 3. Inner well pipe; 31. First impermeable section of inner well pipe; 32. Permeable section of inner well pipe; 33. Second impermeable section of inner well pipe; 34. Water inlet of inner well pipe; 35. Ring positioning device; 3501. Inner ring; 3502. Outer ring; 3503. Connecting piece. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] Reference Figures 1 to 5 This embodiment is a reusable groundwater contaminated single well repair device. The engineering application of the present invention is carried out around the tailings pond in a mining area in Inner Mongolia Autonomous Region. The repair target is the high concentration of lead (Pb) in the groundwater within the depth range of 3-6m underground. After detection, it is determined that the groundwater level is about 2.5-2.8m underground. The total length of the outer well pipe is 6m, the impermeable section is 3m, and the filter cage height is set to 0.5m to match the overall well depth. Six filter cages are set in the permeable section and the impermeable section; for other embodiments, the height of the filter cage can also be adjusted according to the specific dimensions of the permeable section and the impermeable section to the same height or different heights, so that the overall repair of the single well is flat. The first impermeable section of the inner well pipe is slightly longer than the impermeable section of the outer well pipe, and is set to 3.2m. Based on the size matching, it is further determined that the length of the inner well pipe permeable section 32 is 2.6m, and the length of the second impermeable section 33 of the inner well pipe is 0.2m.

[0020] The single well repair device is composed of an outer well pipe 1, a filter cage 2 and an inner well pipe 3, all of which are made of steel.

[0021] The outer well pipe 1 is composed of an outer well pipe permeable section 11 and an outer well pipe impermeable section 12. An outer well pipe water inlet hole 13 is provided on the pipe wall of the outer well pipe permeable section 11 to allow groundwater to pass through. A filtering unit 14 is provided on the outside of the outer well pipe permeable section 11 to block large particles in the groundwater.

[0022] In this embodiment, the inner diameter of the outer well pipe 1 is 426 mm, the length of the outer well pipe permeable section 11 and the length of the outer well pipe impermeable section 12 are both 3 m, and the filter unit is filled with fine sand.

[0023] The filter cage 2 is composed of a filter cage cover plate 21, a filter cage outer ring 22 and a filter cage inner ring 23, all of which are made of steel.

[0024] In this embodiment, the height of the filter cage 2 is 0.5m, the diameter of the filter cage cover 21 is 416mm, the diameter of the center hole of the filter cage cover 21 is 31mm, the outer diameter of the filter cage outer ring 22 is 416mm, and the inner diameter of the filter cage inner ring 23 is 31mm; this embodiment uses 2 imperforate cover plates 2102, 22 perforated cover plates 2101, 12 filter cage outer rings 22 and 12 filter cage inner rings 23 to form 12 filter cages, the imperforate cover plates are placed at the top and the bottom, and the others are all perforated cover plates.

[0025] The adsorbent 28 used in this embodiment is a composite material of biochar and iron-manganese oxides, and the particle size of the adsorbent 28 is 1 mm. The adsorbent 28 is filled in the 6 filter cages at the bottom, with a total of about 500 kg of adsorbent 28 filled. The adsorbent 28 and the filter cages 2 are separated by geotextiles to ensure that the adsorbent 28 will not be lost through the water inlet holes 27 of the filter cages; the 6 filter cages 2 at the top are filled with clay, and the clay and the filter cages 2 are separated by geotextiles to ensure that the clay will not flow out through the water inlet holes 27 of the filter cages.

[0026] The inner well pipe 3 is composed of a first watertight inner well pipe section 31, a water-permeable inner well pipe section 32, a second watertight inner well pipe section 33 and a circular fixing device 35, all of which are made of steel. An inner well pipe water inlet hole 34 is provided on the wall of the water-permeable inner well pipe section 32 to allow groundwater to pass through. The outer diameter of the inner well pipe 3 is 26 mm.

[0027] The inner diameter of the inner ring 3501 in the ring positioning device 35 is 28 mm, the thickness is 4 mm, and the height is 50 mm. The outer diameter of the outer ring 3502 is 416 mm, the thickness is 4 mm, and the height is 50 mm. The length of the connecting piece 3503 is 186 mm, and the height is 50 mm.

[0028] The installation steps of the single well repair device in this embodiment include: preparing all the above components as required, using an engineering drill to drill a hole at the target point with a hole diameter of 600 mm and a hole depth of 6 m, wrapping gauze on the outside of the outer well pipe permeable section 11 to prevent the inflow of large particles, placing the outer well pipe 1 into the drilled hole and filling the outer side of the outer well pipe with fine sand as the filter unit 14 of the single well repair device, using a submersible pump to quickly pump out the groundwater in the outer well pipe 1 until the water is clear, inserting the second impermeable section 33 of the inner well pipe into the inner ring 3501 of the circular positioning device 35, fixing the two together by welding, placing the inner well pipe 3 into the outer well pipe 1, with the circular positioning device 35 facing downward, at this time the inner well pipe 3 remains parallel to the outer well pipe 1, and using a steel wire rope to tighten and stack 6 filter cages filled with adsorbent and 6 filter cages filled with clay from bottom to top.

[0029] like Figure 1As shown, the implementation method of groundwater pollution remediation in this embodiment is as follows: a water pump is connected to the top of the inner well pipe 3 to extract groundwater, driving the contaminated groundwater in the aquifer at a depth of 3-6m to flow from the outside to the inside along the single well remediation device. The groundwater first flows through the filter unit, and the large particles in the groundwater are intercepted by the filter unit. Then, after passing through the outer well pipe water inlet hole 13 and the filter cage water inlet hole 27, it contacts with the adsorbent 28, and the pollutant Pb in the groundwater is removed by adsorption. The clean groundwater after remediation is pumped out by the water pump through the inner well pipe water inlet hole 34 for production and life use. The outer well pipe impermeable section is slightly deeper than the groundwater level, the first impermeable section of the inner well pipe is slightly deeper than the outer well pipe impermeable section, and the stacking height of the filter cage filled with adsorbent is level with the outer well pipe impermeable section. Through the above-mentioned size design, sufficient adsorption and filtration of groundwater is ensured, while avoiding the preferential flow of groundwater in the gaps of the filter cage stacking.

[0030] In this embodiment, the pumping rate of groundwater is set to 10L / h, and the concentration of Pb in groundwater changes with time as shown in Figure 5 As shown in the figure, it can be seen that the initial Pb concentration of the groundwater is 0.17 mg / L, which exceeds the national standard limit by 17 times. After the single-well remediation device has been in operation for 1.4 days, the Pb concentration in the groundwater is reduced to below the detection limit of the flame atomic absorption spectrophotometer, which meets the requirement of less than 0.01 mg / L in my country's "Groundwater Quality Standard" (GB / T 14848-2017). During the 16-day monitoring period, the Pb concentration in the groundwater is maintained at a low level, indicating that the reusable groundwater pollution single-well remediation device provided by the present invention has good groundwater pollution remediation effect and can operate stably.

[0031] The steps for reusing the single well repair device in this embodiment include: regularly testing the water quality of the single well repair device. When the Pb concentration of the effluent is close to 0.01 mg / L, 12 filter cages 2 are taken out from the outer well pipe 1 from top to bottom in sequence by using a wire rope, and the filter cage upper cover 21 of the 6 filter cages 2 with adsorbent 28 at the bottom is opened by removing the screws 26, and the expired adsorbent 28 in the 6 filter cages 2 is taken out, and after filling in new adsorbent 28, the screws 26 are screwed back to fix the filter cage upper cover 21, and the 12 filter cages 2 are put back into the outer well pipe 1 in the order before being taken out by using a wire rope. At this time, the single well repair device is reused.

[0032] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A reusable groundwater contaminated single well repair device, characterized by: From the outside to the inside, there are an outer well pipe (1), a filter cage (2) and an inner well pipe (3), and a plurality of filter cages (2) are provided, which are stacked and sleeved between the inner well pipe (3) and the outer well pipe (1); The outer well pipe (1) comprises a lower outer well pipe water-permeable section (11) and an upper outer well pipe water-impermeable section (12); an outer well pipe water inlet hole (13) is provided on the pipe wall of the outer well pipe water-permeable section (11); The filter cage is composed of a filter cage cover plate (21), a filter cage outer ring (22) and a filter cage inner ring (23); the filter cage outer ring (22) and the filter cage inner ring (23) are both provided with filter cage water inlet holes (27); The inner well pipe (3) is composed of, from top to bottom, a first water-impermeable section (31) of the inner well pipe, a water-permeable section (32) of the inner well pipe, a second water-impermeable section (33) of the inner well pipe, and a circular positioning device (35); an inner well pipe water inlet hole (34) is provided on the wall of the water-permeable section (32) of the inner well pipe; The bottom of the first watertight section (31) of the inner well pipe is longer than the bottom of the watertight section (12) of the outer well pipe, and the length of the second watertight section (33) of the inner well pipe is greater than the height of the circular positioning device (35).

2. A reusable groundwater contaminated single well repair device according to claim 1, characterized in that: The filter cage (2) is filled with filter material, and the filter material is an adsorbent (28) or clay (29); the filter cage cover plate (21) comprises a non-porous cover plate (2102) and a perforated cover plate (2101), and a geotextile is laid between the filter cage (2) and the filter material.

3. The reusable groundwater contaminated single well repair device according to claim 1 is characterized by: The circular ring positioning device (35) is composed of an inner circular ring (3501), an outer circular ring (3502) and a connecting piece (3503); the outer circular ring (3502) is connected and fixed to the inner circular ring (3501) by welding via three groups of connecting pieces (3503); and the inner circular ring (3501) is connected to the second watertight section (33) of the inner well pipe by welding.

4. The reusable groundwater contaminated single well repair device according to claim 1 is characterized by: A plurality of screw holes (24) are provided on the filter cage cover plate (21); the outer screw holes (24) are connected and fixed to the filter cage outer ring (22), and the inner screw holes (24) are connected and fixed to the filter cage inner ring (23).

5. A reusable groundwater contaminated single well repair device according to claim 4, characterized in that: Four nuts (25) are respectively provided on the inner sides of the upper and lower parts of the filter cage outer ring (22) and the filter cage inner ring (23) to be connected and fixed to the filter cage cover plate (21).

6. A reusable groundwater contaminated single well repair device according to any one of claims 1 to 5, characterized in that: The outer well pipe (1) and the inner well pipe (3) are 6-12 m long, the filter cage (2) is 0.5-1 m long, the inner diameter of the outer well pipe (1) is 1 cm longer than the outer diameter of the filter cage outer ring (22), the outer diameter of the inner well pipe (3) is 0.5 cm shorter than the inner diameter of the filter cage inner ring (23), and the diameter of the outer ring (3502) of the ring positioning device (35) is consistent with the outer ring (22) of the filter cage.

7. A method for installing and using a reusable groundwater contaminated single well repair device according to any one of claims 1 to 5, characterized in that: The steps include: Step (1), detecting and determining the depth of the groundwater level, and determining the depth of the repair well, the depth range of the impermeable section and the permeable section of the outer well pipe, and the height of the filter cage according to the water level and the water-richness of the aquifer; Step (2), drilling a repair well with a drilling rig, winding yarn on the outside of an outer well pipe and arranging it in the repair well, and filling fine sand on the outside of the outer well pipe as a filtering unit of the single well repair device; Step (3), placing the inner well tube into the outer well tube, with the circular positioning device placed at the bottom; Step (4), assembling a plurality of filter cages, stacking and installing them one by one between the outer well pipe and the inner well pipe, placing a geotextile in the filter cages and filling them with an adsorbent or clay, the filter cages filled with adsorbents are stacked in the water-permeable section of the outer well pipe, and the filter cages filled with clay are stacked in the water-impermeable section of the outer well pipe, the top cover plate of the filter cage and the bottom cover plate of the filter cage are non-porous cover plates, and the other parts are all perforated cover plates; Step (5), connect a water pump to the top of the inner well pipe.

8. The installation and use method according to claim 7, characterized in that: The method further includes step (6), wherein when the adsorbent in the filter cage reaches adsorption saturation, the filter cages are taken out one by one, the adsorbent is replaced, and the filter cages are stacked again and loaded into the repair well.

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