A test device for indoor simulation of pollutant migration behavior in aquifers and composite anti-fouling barriers

Abstract

The present invention provides a test device capable of simulating the migration behavior of pollutants in an aquifer and a composite anti-pollution barrier indoors, comprising a soil column sleeve, a plurality of first interfaces are arranged along the height direction thereof, and a second interface is arranged at the top of the soil column sleeve; an annular column net barrel is arranged inside the soil column sleeve, and the test device is provided with a removable conical partition net that can be placed in the annular column net barrel, and the interior of the annular column net barrel can be divided into an upper filling chamber and a lower filling chamber through which water can flow; the heights at which the upper and lower ends of the conical partition net are located correspond to a first interface respectively; and the soil column sleeve is filled with aquifer media around the annular column net barrel. The present invention can simulate the migration behavior of pollutants in a multi-medium vertical anti-pollution barrier and an aquifer on a small scale, and solve the inevitable side wall leakage problem in traditional soil column experiments and model experiments by adopting an annular sample loading design, while realizing grouped and layered parallel sampling to improve experimental efficiency.

Description

Technical Field

[0001] The invention relates to an indoor soil column experimental device, which is used for simulating the migration behavior of pollutants in a composite vertical anti-pollution barrier and an aquifer, and belongs to the technical field of environmental engineering research. Background Art

[0002] Vertical anti-pollution barrier technology is also the most effective technology for limiting the migration of groundwater pollutants. Vertical anti-pollution barrier technology can be divided into two types according to the permeability of the barrier material: (i) low-permeability vertical anti-seepage wall; (ii) high-permeability reactive barrier (PRB). The vertical anti-seepage wall uses natural or artificial materials to isolate polluted groundwater from the surrounding uncontaminated areas, preventing pollutants in the controlled contaminated groundwater from spreading outward, and preventing uncontaminated groundwater from entering the controlled contaminated area.

[0003] The design of vertical anti-fouling barrier materials plays a decisive role in the service performance of the barrier. Generally, the migration behavior of pollutants in the barrier material can be simulated by a soil column test of a single medium, so as to determine the migration parameters of pollutants. However, the soil column test of a single medium cannot be used for the working conditions of a composite barrier with multiple media, nor can it consider the influence of aquifers on the migration of pollutants. In the past, only large-volume model tests could be used to simulate the migration behavior of pollutants in aquifers and composite barrier systems.

[0004] Traditional model experiments occupy a large area, have a long experimental cycle, high production costs, and are prone to side wall leakage. Summary of the invention

[0005] To solve this problem, the present invention provides a new type of soil column experimental device, which can simulate the migration behavior of pollutants in multiple medium vertical anti-pollution barriers and aquifers on a small scale, and solve the inevitable side wall leakage problem in traditional soil column experiments and model tests by adopting a ring-shaped sampling design, while realizing grouped and layered parallel sampling to improve experimental efficiency.

[0006] The invention discloses an experimental device for simulating the migration behavior of pollutants in an aquifer and a composite anti-pollution barrier indoors, characterized in that it comprises a soil column sleeve, wherein the soil column sleeve is provided with a plurality of first interfaces along its height direction, wherein the first interfaces are used to connect with an outflow liquid collection system; a second interface is provided at the top of the soil column sleeve, wherein the second interface is used to connect with an interface of a water head control system; an annular column net barrel is provided in the soil column sleeve, wherein the annular column net barrel comprises an inner cylindrical net and an outer cylindrical net, wherein the diameter of the outer cylindrical net is smaller than the inner diameter of the soil column sleeve, and the inner cylindrical net and the outer cylindrical net are connected as a whole at the bottom through a bottom net; the experimental device is provided with a removable conical surface partition net which can be placed in the annular column net barrel, and the interior of the annular column net barrel can be divided into an upper filling chamber and a lower filling chamber through which water can flow; the upper filling chamber and the lower filling chamber are used to fill different media according to different experiments, and are separated by the conical surface partition net, wherein the heights of the upper end and the lower end of the conical surface partition net correspond to a first interface respectively; the soil column sleeve is filled with aquifer media around the annular column net barrel.

[0007] On the basis of adopting the above technical solutions, the present invention may also adopt the following further technical solutions, or use these further technical solutions in combination:

[0008] The soil column sleeve comprises an outer sleeve, a base and a top cover, and the outer sleeve, the base and the top cover are all made of organic glass.

[0009] A waterproof rubber ring is installed at the connection between the outer sleeve and the base and the top cover to prevent pore water from leaking from the side wall; threaded holes are provided at the edges of the outer sleeve and the base and the top cover, and the back is connected and fixed by a long nut and a nut.

[0010] The soil column sleeve is provided with a plurality of first interfaces along its height direction, and at each height, a plurality of first interfaces are evenly provided along the circumferential direction of the soil column sleeve.

[0011] The upper filling chamber is filled with permeable reaction materials according to the experimental requirements; the lower filling chamber is filled with anti-seepage materials according to the experimental requirements; the aquifer is filled with corresponding quartz sand or sandy soil according to the permeability coefficient of the site soil layer.

[0012] When conducting an experiment simulating the migration of pollutants in a PRB, the conical screen is removed and both the upper and lower filling chambers are filled with permeable reactive materials.

[0013] The conical surface separator adopts an organic gauze, and the angle between the conical surface and the axis is 45°.

[0014] The outer cylindrical net is installed with geomembrane GM and geotextile blanket GCL to form a GM / GCL composite vertical anti-fouling barrier.

[0015] The present invention divides the sample into different zones according to different fillers and adopts an annular medium sample loading design to simulate the migration behavior of pollutants in anti-pollution barriers and aquifers of multiple media on a small scale, and solves the inevitable side wall leakage problem in traditional soil column experiments and model experiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a longitudinal cross-sectional view of an embodiment of the present invention.

[0017] Figure 2 It is a transverse cross-sectional view of an embodiment of the present invention. DETAILED DESCRIPTION

[0018] Refer to the attached drawings. A test device capable of simulating the migration behavior of pollutants in an aquifer and a composite anti-pollution barrier indoors, comprising a soil column sleeve, the soil column sleeve comprising an outer sleeve 10, a base 9, and a top cover 8, the outer sleeve 10, the base 9, and the top cover 8 are all made of organic glass. A waterproof rubber ring is installed at the connection between the outer sleeve 10, the base 9, and the top cover 8 to prevent pore water from leaking from the side wall; threaded holes are provided at the edges of the outer sleeve 10, the base 9, and the top cover 8, and the back is connected and fixed by a long nut and a nut.

[0019] The soil column sleeve is provided with a plurality of first interfaces 7 along its height direction to monitor the outflow flow and concentration of soil columns at different depths in real time. The first interface 7 is used to connect to the outflow collection system; a second interface 6 is provided at the top of the soil column sleeve, and the second interface 6 is used to connect to the water head control system interface 6. The water head control device can adopt a Marsh flask, which is fixed on the top of the soil column tube by a bracket, and the second interface 6 is connected by a conduit to ensure that the pollutant solution with a constant water head continuously flows into the soil column; an annular column net barrel 4 is provided in the soil column sleeve, and the annular column net barrel 4 includes an inner cylindrical net 41 and an outer cylindrical net 42, and the diameter of the outer cylindrical net 42 is smaller than the inner diameter of the soil column sleeve, and the inner cylindrical net 41 and the outer cylindrical net 42 are connected as a whole at the bottom through a bottom net 43, and the annular column net barrel 4 is a rigid net tube, and the inner cylindrical net 41 forms a central hole 44 that runs through the upper and lower parts of the annular column net barrel 4.

[0020] The test device is provided with a removable conical partition net 1 which can be placed in the annular column net barrel, and can divide the interior of the annular column net barrel 4 into an upper filling chamber 21 and a lower filling chamber 22 through which water can flow; the upper filling chamber 21 and the lower filling chamber 22 are used to fill different media according to different experiments, and are separated by the conical partition net 1, and the heights at the upper and lower ends of the conical partition net 1 respectively correspond to a first interface 7; the inside of the soil column sleeve is filled with aquifer 3 media around the annular column net barrel 4, and the aquifer 3 media is filled in the central hole 44, between the outer cylindrical net 42 and the outer sleeve 10, and below the annular column net barrel 4, and the aquifer 3 media at different positions are connected.

[0021] The soil column sleeve is provided with a plurality of first interfaces 7 along its height direction. At each height, a plurality of first interfaces 7 are evenly arranged along the circumferential direction of the soil column sleeve. In the present embodiment, three first interfaces 7 are arranged at each height. Sampling at three water outlets can form three groups of parallel tests as self-control, without setting up parallel tests separately.

[0022] When conducting a simulation experiment on the migration of pollutants in the PRB composite anti-seepage wall, the upper filling chamber 21 is used as a permeability reaction chamber, and is filled with permeability reaction materials such as zero-valent iron, activated carbon, zeolite, quartz sand, wood ash, sawdust, microorganisms, peat, etc. according to the experimental requirements; the lower filling chamber 22 is used as an anti-seepage chamber, and is filled with anti-seepage materials such as bentonite, montmorillonite, kaolin, concrete, etc. according to the experimental requirements. Among them, the aquifer 3 is filled with corresponding quartz sand or sandy soil according to the permeability coefficient of the site soil layer. In order to effectively control the flow field in the soil column, it is necessary to control the permeability coefficient of the permeability reaction material to be more than one order of magnitude greater than the permeability coefficient of the aquifer, and the permeability coefficient of the anti-seepage material to be less than 10 -9 m / s, and the permeability coefficient is controlled to be more than one order of magnitude lower than that of the aquifer.

[0023] The conical surface separation net 1 plays a drainage role and can be made of an organic mesh with good water permeability and corrosion resistance. The angle between the conical surface and the axis is 45°.

[0024] The outer cylindrical net 42 can be selectively installed with a geomembrane GM and a geotextile blanket GCL to form a GM / GCL composite vertical anti-fouling barrier.

[0025] When conducting an experiment simulating the migration of pollutants in a PRB, the conical screen 1 is removed, and both the upper filling chamber 21 and the lower filling chamber are filled with permeable reactive materials.

[0026] The present invention will be further described below through the test process:

[0027] In order to simulate the effect of PRB composite anti-seepage wall technology on site pollution control, the aquifer sand, anti-seepage material and active material are respectively filled into the aquifer, the permeability reaction chamber (upper filling chamber 21) and the anti-seepage chamber (lower filling chamber 22). First, a leaching experiment is carried out. The Malchnitz flask is filled with deionized water and fixed above the soil column by a bracket. The height of the Malchnitz flask is set according to the head required by the experiment. The bottom of the Malchnitz flask is connected to the second interface 6 of the soil column sleeve through a conduit. Close the valve of the effluent collection port on the side wall of the soil column, and only open the three effluent collection port valves at the bottom of the soil column to allow water to flow into the sleeve from the top of the soil column sleeve and flow out from the bottom of the soil column sleeve. Collect the effluent every 12 hours, and measure the volume and conductivity. When the effluent volume and conductivity reach a constant, the leaching is completed. At this time, close the valve of the inlet at the top of the soil column, replace the solution in the Martens flask with the pollutant solution, open the inlet valve, let the pollutant solution enter the soil column under the action of the water head, and flow out from the outflow collection port on the side wall of the soil column through media with different permeability coefficients. Collect the outflow liquid every 12 hours, and measure the outflow liquid volume, conductivity and pollutant concentration to obtain the change of pore water concentration at different depths over time. Finally, the unit body is modeled by Hydrus3D software, and the experimental data is imported. Through inverse analysis and calculation, the outflow curve is fitted to obtain the temporal and spatial distribution of pollutants in the system, so as to evaluate the effect of the PRB composite anti-seepage wall measures.

[0028] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A test device that can simulate the migration behavior of pollutants in aquifers and composite anti-pollution barriers indoors, characterized by The invention comprises a soil column sleeve, wherein the soil column sleeve is provided with a plurality of first interfaces (7) along its height direction, wherein the first interfaces (7) are used to be connected to an outflow liquid collection system; a second interface (6) is provided at the top of the soil column sleeve, wherein the second interface (6) is used to be connected to an interface of a water head control system; an annular column net barrel (4) is provided in the soil column sleeve, wherein the annular column net barrel (4) comprises an inner cylindrical net (41) and an outer cylindrical net (42), wherein the diameter of the outer cylindrical net (42) is smaller than the inner diameter of the soil column sleeve, wherein the inner cylindrical net (41) and the outer cylindrical net (42) are connected as a whole at the bottom through a bottom net (43), wherein the inner cylindrical net (41) forms a central hole (44) which passes through the upper and lower parts of the annular column net barrel (4); the test The device is provided with a removable conical partition net (1) which can be placed in the annular column net barrel, and can divide the interior of the annular column net barrel (4) into an upper filling chamber (21) and a lower filling chamber (22) through which water can flow; the upper filling chamber (21) and the lower filling chamber (22) are used to fill different media according to different experiments, and are separated by the conical partition net (1), and the heights at which the upper end and the lower end of the conical partition net (1) are located correspond to a first interface (7) respectively; the soil column sleeve is filled with aquifer (3) medium around the annular column net barrel (4), and the aquifer (3) medium is filled in the central hole (44), between the outer cylindrical net (42) and the outer sleeve (10), and below the annular column net barrel (4).

2. The test device for simulating the migration behavior of pollutants in an aquifer and a composite anti-fouling barrier in an indoor environment as claimed in claim 1, characterized in that: The soil column sleeve comprises an outer sleeve (10), a base (9), and a top cover (8); the outer sleeve (10), the base (9), and the top cover (8) are all made of organic glass.

3. The test device for simulating the migration behavior of pollutants in an aquifer and a composite anti-fouling barrier in an indoor environment as claimed in claim 2, characterized in that: A waterproof rubber ring is installed at the connection between the outer sleeve (10) and the base (9) and the top cover (8) to prevent pore water from leaking from the side wall; threaded holes are provided at the edges of the outer sleeve (10) and the base (9) and the top cover (8), and the back is connected and fixed by a long nut and a nut.

4. The test device for simulating the migration behavior of pollutants in an aquifer and a composite anti-fouling barrier in an indoor environment as claimed in claim 1, characterized in that: The soil column sleeve is provided with a plurality of first interfaces (7) along its height direction, and at each height, a plurality of first interfaces are evenly provided along the circumferential direction of the soil column sleeve.

5. The test device for simulating the migration behavior of pollutants in an aquifer and a composite anti-fouling barrier in an indoor environment as claimed in claim 1, characterized in that: The upper filling chamber (21) is filled with permeable reaction materials according to the experimental requirements; the lower filling chamber (22) is filled with anti-seepage materials according to the experimental requirements; and the aquifer (3) is filled with corresponding quartz sand or sandy soil according to the permeability coefficient of the soil layer of the site.

6. The test device for simulating the migration behavior of pollutants in an aquifer and a composite anti-fouling barrier in an indoor environment as claimed in claim 1, characterized in that: When conducting an experiment simulating the migration of pollutants in a PRB, the conical screen (1) is removed, and the upper filling chamber (21) and the lower filling chamber (22) are both filled with permeable reactive materials.

7. The test device for simulating the migration behavior of pollutants in an aquifer and a composite anti-fouling barrier in an indoor environment as claimed in claim 1, characterized in that: The conical surface separator (1) is made of an organic gauze, and the angle between the conical surface and the axis is 45°.

8. The test device for simulating the migration behavior of pollutants in an aquifer and a composite anti-fouling barrier in an indoor environment as claimed in claim 1, characterized in that: The outer cylindrical net (42) is installed with a geomembrane GM and a geotextile blanket GCL to form a GM / GCL composite vertical anti-fouling barrier.

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