Device for microbial remediation of heavy metal contaminated soil

Abstract

The utility model belongs to the technical field of soil remediation, and relates to a device for remedying heavy metal contaminated soil by microorganisms, which comprises an outer sleeve, an inner sleeve, a connecting pipe, an inflating pipe and an air bag, a plurality of grouting holes are formed in the side wall of the outer sleeve, and a conical head is arranged at the bottom; the inner sleeve is arranged in the outer sleeve, a top sealing plate and a bottom sealing plate are fixed to the upper end and the lower end of the inner sleeve respectively, and annular sealing rings are fixed to the outer side wall of the top sealing plate and the outer side wall of the bottom sealing plate. A plurality of through grooves which are annularly distributed are formed in the side wall of the inner sleeve; the bottom end of the connecting pipe penetrates through the top sealing plate and is fixedly connected with the top sealing plate; the bottom end of the inflating pipe penetrates through the bottom sealing plate and is fixedly connected with the bottom sealing plate; an inflation opening in the top of the airbag is in threaded connection with the bottom end of the inflation pipe. According to the device, the microbial cementing liquid can be poured in a sectional manner by lifting the inner sleeve, the air bag is inflated to expand so as to fill the inner cavity of the outer sleeve between the bottom sealing plate and the conical head, the microbial cementing liquid filled in the outer sleeve can be reduced, and waste is reduced.

Description

Technical Field

[0001] This invention belongs to the field of soil remediation technology, and in particular relates to a device for microbial remediation of heavy metal contaminated soil. Background Technology

[0002] Microbial induced carbonate precipitation (MICP) is a novel, environmentally friendly solidification technology. It utilizes specific microorganisms that produce carbonic anhydrase during their life processes, generating a large number of carbonate ions to fix heavy metals. This technology can be used to remediate soil contaminated with heavy metals. Using grouting equipment such as grouting pipes and pumps, the microbial binder is injected into the contaminated soil, allowing it to diffuse under grouting pressure. This enables in-situ remediation with minimal disturbance at the contaminated site. Furthermore, the diameter of microorganisms (bacteria) is only a few micrometers, far smaller than the average particle diameter in cement grout. Therefore, the diffusion range of the microbial binder injected into the soil is significantly greater than that of traditional cement grouting under the same pressure.

[0003] The existing grouting pipes do not use layered grouting during construction, which leads to the inside of the grouting pipes being filled with grout. This is especially true when injecting microbial cementitious liquid to remediate soil contaminated with heavy metals. Microbial cementitious liquid is more expensive than traditional cement grout, and the inside of the grouting pipe being filled with microbial cementitious liquid will result in material waste and high costs. Utility Model Content

[0004] The purpose of this invention is to provide a device for microbial remediation of heavy metal contaminated soil. This device can be used for layered grouting, which helps to reduce the amount of microbial cementing liquid filling the grouting pipe, thereby solving the problems mentioned in the background art.

[0005] This utility model is achieved through the following technical solution:

[0006] A device for microbial remediation of heavy metal contaminated soil includes an outer casing with several grouting holes on its sidewalls and a cone-shaped tip at its bottom for easy insertion into a borehole and the soil at the bottom of the borehole.

[0007] The device includes an inner sleeve disposed inside an outer sleeve and movable along the axial direction of the outer sleeve. A top sealing plate and a bottom sealing plate are fixed to the upper and lower ends of the inner sleeve, respectively. An annular sealing ring is fixed to the outer wall of both the top and bottom sealing plates. The annular sealing ring seals the gaps between the top sealing plate and the outer sleeve, and between the bottom sealing plate and the outer sleeve. The annular sealing ring moves axially within the outer sleeve along with the inner sleeve, and slides against the inner wall of the outer sleeve to form a seal, similar to the fit between the piston inside a syringe and the outer barrel of a syringe. Multiple annularly distributed through grooves are provided on the side wall of the inner sleeve, allowing communication between the interior of the inner sleeve and the interior of the outer sleeve.

[0008] Includes a connecting pipe, the bottom end of which penetrates the top sealing plate and is fixedly connected to the top sealing plate. The interior of the connecting pipe is connected to the interior of the inner sleeve. Microbial cementing solution can be injected into the inner sleeve through the connecting pipe. The microbial cementing solution in the inner sleeve can flow from each through groove into the annulus between the inner sleeve and the outer sleeve, and then be injected into the borehole and soil through the grouting hole.

[0009] Includes an inflation tube, which is inserted into a connecting tube, and the bottom end of the inflation tube passes through the bottom sealing plate and is fixedly connected to the bottom sealing plate;

[0010] It includes an airbag, which is disposed between the bottom sealing plate and the cone head. The air inlet at the top of the airbag is threadedly connected to the bottom end of the inflation tube, and air can be inflated into the airbag through the inflation tube.

[0011] Furthermore, the cone head is threadedly connected to the outer sleeve, which facilitates the assembly and disassembly of the cone head. The bottom end of the airbag is fixed to the cone head. When inflated using the inflation tube, the airbag expands to fill the cavity between the inner bottom sealing plate of the outer sleeve and the cone head, thereby reducing the amount of microbial cementing liquid filling this cavity.

[0012] Furthermore, the top end of the inner sleeve is threaded to the top sealing plate or the bottom end of the inner sleeve is threaded to the bottom sealing plate, so that the inner sleeve can be disassembled and assembled with the top sealing plate or the bottom sealing plate, which facilitates cleaning and maintenance of the inside of the inner sleeve.

[0013] Furthermore, the device also includes a three-way pipe, the bottom end of which is detachably connected to the top end of the connecting pipe. A top cap is connected to the top end of the three-way pipe, an inner connector is fixed to the inner top surface of the top cap, and an outer connector is fixed to the outer top surface of the top cap. The inner connector and the outer connector are connected. The top end of the inflation pipe is connected to the inner connector. The outer connector is used to connect to an external inflation pipe. The side end of the three-way pipe is used to connect to a pumping pipe for the microbial cementing liquid. The pumping device pumps the microbial cementing liquid from the side end of the three-way pipe into the interior of the connecting pipe. The inflation device inflates the airbag by inflating the inflation pipe through the outer connector.

[0014] Furthermore, the connecting pipe is composed of a fixed pipe and a combined pipe. The bottom end of the fixed pipe passes through the top sealing plate and is fixedly connected to the top sealing plate. Its top end is threadedly connected to the bottom end of the combined pipe, and the top end of the combined pipe is threadedly connected to the bottom end of the tee pipe. The connecting pipe has a combined structure, which facilitates maintenance and transportation.

[0015] Furthermore, the inflation tube consists of an inflation rigid tube and an inflation flexible tube. The bottom end of the inflation rigid tube passes through the bottom sealing plate and is fixedly connected to the bottom sealing plate. Both ends of the inflation flexible tube are provided with threaded connectors for connecting the top end of the inflation rigid tube and the inner connector. During assembly, the threaded connector at the bottom end of the inflation flexible tube is threadedly connected to the top end of the inflation rigid tube. The two ends of the combined tube are threadedly connected to the fixed tube and the tee tube, respectively. The inflation flexible tube is inserted inside the combined tube and the tee tube. The threaded connector at the top end of the inflation flexible tube is threadedly connected to the inner connector on the top cap. Finally, the top cap is threadedly connected to the top end of the tee tube. When the top cap is threadedly connected to the tee tube, the inflation flexible tube can rotate when the top cap is turned, because the inflation flexible tube is a flexible tube structure.

[0016] Furthermore, multiple ribs arranged in a ring are welded between the bottom outer wall of the fixed pipe and the top surface of the top sealing plate, which can improve the structural strength and stability. When grouting, pulling the connecting pipe upward can drive the inner sleeve to move upward inside the outer sleeve.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] This device can be used to inject microbial cementing solution into soil during the remediation of heavy metal soil using microbial induced carbonate precipitation technology. By raising the inner sleeve, the microbial cementing solution can be injected in stages. During the injection process, the airbag is inflated to fill the cavity inside the outer sleeve between the bottom sealing plate and the cone head, which reduces the amount of microbial cementing solution filling the outer sleeve. The airbag can also push the inner sleeve upward. This device allows for layered grouting, which helps to reduce the waste of microbial cementing solution in the injection pipeline. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0020] Figure 1 This is a cross-sectional structural diagram of the present invention;

[0021] Figure 2 for Figure 1 A schematic diagram of a local structure in the image;

[0022] Figure 3 This is a three-dimensional structural diagram of the present invention;

[0023] Figure 4 This is a schematic diagram of the exploded structure of this utility model.

[0024] The components in the diagram are named as follows: 1. Outer sleeve; 1.1. Grouting hole; 2. Airbag; 3. Cone head; 4. Bottom sealing plate; 5. Inner sleeve; 5.1. Through groove; 6. Top sealing plate; 7. Inflation pipe; 7.1. Inflation rigid pipe; 7.2. Inflation flexible hose; 8. Connecting pipe; 8.1. Fixing pipe; 8.2. Combination pipe; 9. T-pipe; 10. Top cap; 11. Annular sealing ring; 12. Inner connector; 13. Outer connector; 14. Rib plate. Detailed Implementation

[0025] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0026] In the description of this application, it should be understood that the terms "upper", "lower", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0027] A device for microbial remediation of heavy metal contaminated soil, such as Figures 1 to 4 As shown, it mainly consists of an outer sleeve 1, an inner sleeve 5, a top sealing plate 6, a bottom sealing plate 4, a connecting pipe 8, an inflation pipe 7, a three-way pipe 9, a cone head 3, and an airbag 2;

[0028] The outer casing 1 has several grouting holes 1.1 on its side wall, so that the microbial cementing solution pumped into the outer casing 1 can be injected into the soil through the grouting holes 1.1.

[0029] The inner sleeve 5 is disposed inside the outer sleeve 1 and can move along the axial direction of the outer sleeve 1. The top sealing plate 6 is welded to the top of the inner sleeve 5 and the bottom end of the inner sleeve 5 is threadedly connected to the bottom sealing plate 4, which facilitates disassembly and assembly. After disassembly, it is convenient to clean and maintain the inside of the inner sleeve 5. The side wall of the inner sleeve 5 is provided with multiple through grooves 5.1 distributed in a ring, so that the inside of the inner sleeve 5 communicates with the inside of the outer sleeve 1.

[0030] An annular sealing ring 11 is fixed to the outer side wall of the top sealing plate 6 and the outer side wall of the bottom sealing plate 4. The annular sealing ring 11 can be used to seal the gap between the top sealing plate 6 and the outer sleeve 1, and between the bottom sealing plate 4 and the outer sleeve 1. The annular sealing ring 11 can move axially in the outer sleeve 1 with the inner sleeve 5. The annular sealing ring 11 slides and forms a seal with the inner side wall of the outer sleeve 1, similar to the fit structure between the piston inside the syringe and the outer barrel of the syringe.

[0031] The bottom end of the connecting pipe 8 penetrates the top sealing plate 6 and is fixedly connected to the top sealing plate 6. The interior of the connecting pipe 8 is connected to the interior of the inner sleeve 5. Microbial cementing liquid can be injected into the inner sleeve 5 through the connecting pipe 8. The microbial cementing liquid in the inner sleeve 5 can enter the annulus between the inner sleeve 5 and the outer sleeve 1 from each through groove 5.1, and then be injected into the borehole and soil through the grouting hole 1.1.

[0032] The inflation tube 7 is inserted into the connecting tube 8, and the bottom end of the inflation tube 7 passes through the bottom sealing plate 4 and is fixedly connected to the bottom sealing plate 4.

[0033] The bottom end of the three-way pipe 9 is threadedly connected to the top end of the connecting pipe 8. A top cap 10 is threadedly connected to the top end of the three-way pipe 9. An inner connector 12 is fixed to the inner top surface of the top cap 10, and an outer connector 13 is fixed to the outer top surface of the top cap 10. The inner connector 12 and the outer connector 13 are connected. The top end of the air inflator 7 is threadedly connected to the inner connector 12. The outer connector 13 is used to connect to an external air inflator. The side end of the three-way pipe 9 is used to connect to a pumping pipe for the microbial cementing liquid. The pumping device pumps the microbial cementing liquid from the side end of the three-way pipe 9 into the interior of the connecting pipe 8. The air inflator inflates the airbag 2 by inflating the air inflator pipe 7 through the outer connector 13. The pumping device is an existing grouting equipment (including a grouting pump and a grouting pipe). The air inflator is an existing air inflator (such as an air compressor or an air pump) for inflating the airbag 2.

[0034] The top end of the cone 3 is threaded to the bottom end of the outer sleeve 1, which facilitates the assembly and disassembly of the cone 3. The pointed cone structure of the cone 3 makes it easy to insert into the borehole and the soil at the bottom of the hole.

[0035] The airbag 2 is disposed between the bottom sealing plate 4 and the cone head 3, and its bottom end is fixed on the cone head 3. The inflation port at the top of the airbag 2 is threadedly connected to the bottom end of the inflation tube 7, and air can be inflated into the airbag 2 through the inflation tube 7. The airbag 2 has a folded structure. When inflated by the inflation tube 7, the airbag 2 is inflated and stretched at the same time as the inner sleeve 5 rises inside the outer sleeve 1, so that the airbag 2 can expand to fill the cavity between the bottom sealing plate 4 and the cone head 3 inside the outer sleeve 1, so as to reduce the filling of the cavity by the microbial cementing liquid.

[0036] Preferably, in this embodiment, such as Figure 1 , Figure 2 and Figure 4 As shown, the connecting pipe 8 consists of a fixed pipe 8.1 and a combined pipe 8.2. The bottom end of the fixed pipe 8.1 passes through the top sealing plate 6 and is welded to the top sealing plate 6. Its top end is threaded to the bottom end of the combined pipe 8.2. The top end of the combined pipe 8.2 is threaded to the bottom end of the tee pipe 9. The connecting pipe 8 has a combined structure, which facilitates maintenance and transportation. Specifically, the combined pipe 8.2 can be spliced ​​from multiple hollow pipes, which facilitates adjustment of its overall length.

[0037] Preferably, in this embodiment, such as Figure 1 , Figure 2 and Figure 4 As shown, the inflation tube 7 consists of an inflation rigid tube 7.1 and an inflation hose 7.2. The bottom end of the inflation rigid tube 7.1 passes through the bottom sealing plate 4 and is welded and fixed to the bottom sealing plate 4. Both ends of the inflation hose 7.2 are provided with threaded connectors for connecting the top end of the inflation rigid tube 7.1 and the inner connector 12. During assembly, the threaded connector at the bottom end of the inflation hose 7.2 is threadedly connected to the top end of the inflation rigid tube 7.1, and both ends of the combined tube 8.2 are threadedly connected to the fixed tube 8.1 and the tee tube 9, respectively. The inflation hose 7.2 is then inserted into the... Inside the combined pipe 8.2 and the tee pipe 9, the threaded connector at the top of the inflatable hose 7.2 is threaded to the inner connector 12 on the top cap 10, and finally the top cap 10 is threaded to the top of the tee pipe 9. When the top cap 10 is threaded to the tee pipe 9, the inflatable hose 7.2 can rotate when the top cap 10 is turned, because the inflatable hose 7.2 is a hose structure. In addition, the top cap 10 and the tee pipe 9, and the tee pipe 9 and the combined pipe 8.2 can also be connected by flange bolts, and a sealing gasket is configured to form a seal.

[0038] Preferably, in this embodiment, such as Figure 1 , Figure 2 and Figure 4 As shown, multiple ribs 14 arranged in a ring are welded between the bottom outer wall of the fixed pipe 8.1 and the top surface of the top sealing plate 6, which can improve the structural strength and stability. When grouting, pulling the connecting pipe 8 upward can drive the inner sleeve 5 to move upward inside the outer sleeve 1.

[0039] The working principle of this device is as follows:

[0040] When using microbial-induced carbonate precipitation technology for heavy metal soil remediation, this device is used to inject microbial cementing solution into the soil. After drilling a borehole on the ground, the assembled device is lowered into the borehole, with the cone 3 inserted into the soil at the bottom of the hole to ensure the stability of the device within the borehole. The side end of the three-way pipe 9 is connected to the pumping device for the microbial cementing solution, and the outer connector 13 is connected to the air injection device. In the initial state, the inner sleeve 5 is located at a low position inside the outer sleeve 1, and the air bladder 2 is in a folded and contracted state. The annulus between the inner sleeve 5 and the outer sleeve 1 is connected through multiple grouting holes 1.1 and the annulus between the outer sleeve 1 and the borehole. The pumping device is started to pump the microbial cementing solution into the inner sleeve 5 through the three-way pipe 9 and the connecting pipe 8. Then, the microbial cementing solution enters the borehole through the through groove 5.1 and the grouting holes 1.1, and... Under pump pressure, the microbial cementing solution is injected into the soil for soil remediation. After the inner sleeve 5 is injected with microbial cementing solution at this depth for a certain period of time, the air injection device is activated to inflate the airbag 2. When the airbag 2 expands, it pushes the bottom sealing plate 4, the inner sleeve 5, and the top sealing plate 6 to rise a certain distance before stopping the inflation. Alternatively, the connecting pipe 8 can be lifted to raise the inner sleeve 5 a certain distance. The inner sleeve 5 then injects microbial cementing solution into the soil again at this depth. The microbial cementing solution is injected in sections according to the above method. During the injection of microbial cementing solution, the airbag 2 is inflated to fill the internal cavity of the outer sleeve 1 between the bottom sealing plate 4 and the cone head 3, which can reduce the amount of microbial cementing solution filled in the outer sleeve 1. The airbag 2 can also push the inner sleeve 5 to rise. This device can be used for layered grouting, which can help reduce the waste of microbial cementing solution.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model, and they should all be covered within the scope of the claims and specification of this utility model.

Claims

1. A device for microbial remediation of heavy metal contaminated soil, comprising an outer tube (1), wherein the side wall of the outer tube (1) is provided with a plurality of grouting holes (1.1), and a cone (3) is provided at the bottom of the outer tube (1), characterized in that: Includes an inner sleeve (5), which is disposed inside the outer sleeve (1). The upper and lower ends of the inner sleeve (5) are respectively fixed with a top sealing plate (6) and a bottom sealing plate (4). The outer side wall of the top sealing plate (6) and the outer side wall of the bottom sealing plate (4) are both fixed with annular sealing rings (11). The side wall of the inner sleeve (5) is provided with multiple through grooves (5.1) distributed in annular shape. Includes a connecting pipe (8), the bottom end of which penetrates the top sealing plate (6) and is fixedly connected to the top sealing plate (6); Includes an inflation tube (7), which is inserted into a connecting tube (8), and the bottom end of the inflation tube (7) passes through the bottom sealing plate (4) and is fixedly connected to the bottom sealing plate (4); Includes an airbag (2), which is disposed between the bottom sealing plate (4) and the cone (3), and the inflation port at the top of the airbag (2) is threadedly connected to the bottom end of the inflation tube (7).

2. The apparatus for microbial remediation of heavy metal contaminated soil according to claim 1, characterized in that: The cone (3) is threadedly connected to the outer sleeve (1), and the bottom end of the airbag (2) is fixed on the cone (3).

3. The apparatus for microbial remediation of heavy metal contaminated soil according to claim 1, characterized in that: The top end of the inner sleeve (5) is threaded to the top sealing plate (6) or the bottom end of the inner sleeve (5) is threaded to the bottom sealing plate (4).

4. The apparatus for microbial remediation of heavy metal contaminated soil according to claim 1, characterized in that: The device also includes a three-way pipe (9), the bottom end of which is detachably connected to the top end of the connecting pipe (8), and a top cap (10) is connected to the top end of which an inner connector (12) is fixed on the inner top surface of the top cap (10), and an outer connector (13) is fixed on the outer top surface of the top cap (10). The inner connector (12) and the outer connector (13) are connected. The top end of the air-filling pipe (7) is connected to the inner connector (12). The outer connector (13) is used to connect to an external air-filling pipe. The side end of the three-way pipe (9) can be used to connect to a pumping pipe for microbial cementing liquid.

5. The apparatus for microbial remediation of heavy metal contaminated soil according to claim 4, characterized in that: The connecting pipe (8) is composed of a fixed pipe (8.1) and a combined pipe (8.2). The bottom end of the fixed pipe (8.1) passes through the top sealing plate (6) and is fixedly connected to the top sealing plate (6). Its top end is threadedly connected to the bottom end of the combined pipe (8.2). The top end of the combined pipe (8.2) is threadedly connected to the bottom end of the tee pipe (9).

6. The apparatus for microbial remediation of heavy metal contaminated soil according to claim 5, characterized in that: The inflation tube (7) consists of an inflation rigid tube (7.1) and an inflation hose (7.2). The bottom end of the inflation rigid tube (7.1) passes through the bottom sealing plate (4) and is fixedly connected to the bottom sealing plate (4). Both ends of the inflation hose (7.2) are provided with threaded joints for connecting the top end of the inflation rigid tube (7.1) and the inner joint (12).

7. The apparatus for microbial remediation of heavy metal contaminated soil according to claim 5, characterized in that: Multiple ribs (14) arranged in a ring are welded between the bottom outer wall of the fixed tube (8.1) and the top surface of the top sealing plate (6).

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