A multifunctional groundwater pollution diffusion and in-situ remediation simulation device and its application

Abstract

The present invention provides a multifunctional groundwater pollution diffusion and in-situ remediation simulation device, including a device body, a liquid supply device and a wastewater recovery and treatment device; the liquid supply device is composed of a liquid distribution tank, a water pump, an upstream water inlet pipe and an upstream overflow pipe, the upstream overflow pipe includes a main pipe, the main pipe is connected with a plurality of upstream drainage pipes of different heights, the upstream drainage pipe is connected with one side of the upstream water tank, and a valve is installed on the upstream drainage pipe; a downstream drainage pipe is opened at the bottom of the downstream water tank, the downstream drainage pipe is a hose, and forms a U-shaped pipe effect with the downstream water tank, and a crack is provided at the highest point of the downstream drainage pipe. The present invention can flexibly adjust the upstream and downstream water level difference according to the hydraulic gradient requirements, monitor the three-dimensional spatiotemporal distribution of the pollution plume, and study the remediation effect of groundwater in-situ injection technology, permeable reaction wall technology, and hydraulic regulation technology on contaminated groundwater.

Description

Technical Field

[0001] The present invention belongs to the technical field of contaminated groundwater remediation, and specifically relates to a multifunctional groundwater contamination diffusion and in-situ remediation simulation device and its application. Background Art

[0002] As an important strategic resource supporting the sustainable development of the economy and society, groundwater plays an irreplaceable role in maintaining the healthy development of the economy and society. However, with the advancement of economic and social development and industrialization, the problem of petroleum hydrocarbon pollution in groundwater has become increasingly prominent. As the "blood" of industry, petroleum is an important basic energy source for the development of the national economy and is widely used in chemical production. In the process of production and transportation, petroleum hydrocarbon pollutants will inevitably enter the groundwater system due to many reasons such as "leakage", production accidents, and the discharge of sewage and waste, thus causing groundwater environmental pollution and seriously threatening people's production and life. Therefore, the treatment of polluted groundwater has become an environmental, economic and social problem that my country must face. At present, the main methods for removing petroleum hydrocarbon pollutants from groundwater include extraction treatment, air disturbance, in-situ chemical oxidation, permeable reaction wall and other technologies, but these technologies often require the injection of a large amount of chemical reagents, with high construction and long-term operation and maintenance costs, and are not ideal for the tailing or rebound phenomenon that occurs in the later stage of pollution remediation. In recent years, in-situ bioremediation has received widespread attention due to its advantages such as small site disturbance, low remediation cost, and environmental friendliness.

[0003] Patent 1 (CN201210501869.5) discloses a groundwater in-situ chemical and biological remediation simulation test device, which includes a seepage trough, an inlet and outlet water buffer trough, a water supply device and a liquid recovery bottle. The seepage trough is connected to the inlet and outlet water buffer troughs through a porous water distribution baffle, and a drainage hole with a valve is provided on the outside of the outlet water buffer trough; a row of injection wells is provided upstream of the seepage trough, and a number of monitoring wells are provided in the trough, and the monitoring wells are equipped with water quality analysis probes; a sealed top plate is provided on the top of the seepage trough and the inlet and outlet water buffer trough, and an inlet and outlet hole are provided on the top plate; a pressure measuring tube is provided on the side wall of the seepage trough. The test method includes: filling the medium, saturating with water, pumping in contaminated groundwater, and adding reagents to simulate the in-situ chemical and biological remediation process. Patent 2 (CN 103336100A) discloses an integrated simulation device for groundwater pollution process and pollution remediation, which includes a simulation tank, which is divided into a front box and a rear box. One side of the front box and the rear box are both open ends. The infiltration reaction wall is installed between the open ends of the two boxes. The two sides of the infiltration reaction wall corresponding to the open ends of the two boxes are provided with vertically arranged sampling holes; the open ends of the two boxes are concave slots for inserting and pulling steel blocking plates; the side walls on both sides of the simulation tank are respectively provided with sampling holes and monitoring holes; the other sides of the two boxes are respectively provided with an upstream water tank and a downstream water tank, and porous plates are respectively installed between the upstream water tank and the downstream water tank and the box; the bottom of the outer wall of the upstream water tank is provided with a water inlet hole, the outer wall of the downstream water tank is provided with vertically arranged overflow holes of different heights, and a water stop valve is provided at the bottom of the outer wall of the downstream water tank. Patent 3 (CN203033844U) discloses a simulation device for in-situ remediation of groundwater pollution, which includes an inlet trough, an outlet trough, a front porous medium simulation trough and a rear porous medium simulation trough arranged between the inlet trough and the outlet trough, a fixed permeable wall is arranged between the inlet trough and the front porous medium simulation trough, and five fixed slots are arranged between the inlet trough and the outlet trough. A permeable wall is inserted in the last fixed slot to form an isolation permeable wall between the rear porous medium simulation trough and the outlet trough, and any two of the other four fixed slots are inserted with permeable walls to form two movable permeable walls, and a reaction wall is between the two movable permeable walls. The utility model can narrow the gap between the simulated environment for in-situ remediation of contaminated groundwater and the actual environment, truly reflect the in-situ remediation status of groundwater pollution, and provide an objective theoretical reference for the engineering application of in-situ remediation technology for groundwater pollution. The above-mentioned prior art has the following problems:

[0004] (1) It is difficult to fix the upstream water level at multiple levels. If the upstream water flow is greater than the sand box seepage flow, the upstream water level will continue to rise; if the water flow is less than the sand box seepage flow, the upstream water level will drop. It is difficult to fix the upstream water level, or it is impossible to fix the water level at different heights as needed.

[0005] (2) The downstream water level cannot be flexibly adjusted. The downstream drainage outlets are mostly arranged at fixed intervals. If the downstream target water level is between two outlets, it is difficult to achieve. The water level can only be adjusted in a jumpy manner, not continuously.

[0006] (3) Existing monitoring wells are difficult to monitor the three-dimensional spatiotemporal distribution of the pollution plume. The lateral sampling holes of the sand boxes of Patents 2 and 3 can only monitor the vertical two-dimensional distribution of pollutants in the aquifer; the monitoring wells arranged in Patent 1 can monitor the horizontal and vertical distribution of pollution, but in order to monitor the water quality at multiple depths, the device arranges one monitoring well at each depth, which wastes materials, occupies space, increases the disturbance to groundwater seepage, and affects accuracy.

[0007] (4) The existing devices can only simulate the remediation effect of pollutants by in-situ injection technology (patent 1) or permeable reaction wall technology (patents 2 and 3), but cannot verify the remediation effect of the composite technology.

[0008] (5) The existing equipment is unable to carry out pumping experiments to simulate the control effect of the natural flow field of groundwater and artificial hydraulic regulation on the pollution plume and the acceleration of the migration of the effective components of the remediation agent.

[0009] (6) There is no wastewater treatment facility downstream of the existing device. In order to simulate the migration process of groundwater, the water in the device is always in a flowing state, and the experiment will generate a large amount of wastewater. Summary of the invention

[0010] The present invention provides a multifunctional groundwater pollution diffusion and in-situ remediation simulation device, which can flexibly adjust the upstream and downstream water level difference according to the hydraulic gradient requirements, monitor the three-dimensional spatiotemporal distribution of the pollution plume, simulate the migration, adsorption and other geochemical behaviors of pollutants in the aquifer medium, and study the remediation effects of groundwater in-situ injection technology, permeable reaction wall technology, and hydraulic regulation technology on contaminated groundwater.

[0011] To achieve the above purpose, the technical solution provided by the present invention is as follows:

[0012] A multifunctional groundwater pollution diffusion and in-situ remediation simulation device, comprising a device body, a liquid supply device and a wastewater recovery and treatment device;

[0013] The device body comprises an upstream water tank, a sand box and a downstream water tank which are connected in sequence, the sand box is filled with a filling medium, the water inlet side of the sand box is connected to the upstream water tank through a water filter plate, and the water outlet side of the sand box is connected to the downstream water tank through a water filter plate;

[0014] The liquid supply device is composed of a liquid distribution tank, a water pump, an upstream water inlet pipe and an upstream overflow pipe. The upstream water inlet pipe is connected to the top of the upstream water tank. The water pump allows the liquid in the liquid distribution tank to enter the upstream water tank through the upstream water inlet pipe. The upstream overflow pipe includes a main pipe, which is connected to a plurality of upstream drainage pipes of different heights. The upstream drainage pipes of different heights are connected to a side of the upstream water tank. A valve is installed on the upstream drainage pipe.

[0015] A hole is provided at the bottom of the downstream water tank, and a downstream drainage pipe is sealed and connected to the hole; the downstream drainage pipe is a hose, forming a U-shaped pipe effect with the downstream water tank, and a crack is provided at the highest point of the downstream drainage pipe; the water outlet of the downstream drainage pipe is located above the wastewater recovery and treatment device;

[0016] A permeable reaction wall, a plurality of monitoring wells and a plurality of injection wells are vertically arranged in the sand box; a plurality of screen tubes and cement are longitudinally arranged in the monitoring well, the screen tubes and cement are alternately arranged, and the cement seals and blocks each screen tube; a plurality of sampling tubes are contained in the monitoring well, and the sampling tubes are directly connected to the screen tubes from the wellhead, and a three-way valve is arranged on the top of the sampling tube, each sampling tube is directly connected to a different screen tube, and the cement fixes the sampling tube; the plurality of injection wells include a first injection well, and the first injection well is located in the middle of the sand box on one side close to the upstream water tank, and the remaining injection wells are evenly distributed in the left part of the sand box close to the upstream water tank, the middle part of the sand box and the right part of the sand box close to the downstream water tank.

[0017] The present invention can flexibly and quickly adjust the downstream water level height and the upstream and downstream water level difference through the structural design of the liquid supply device and the wastewater recovery and treatment device, which is conducive to the stable flow field regulation. The upstream drain pipe valve controls the switch of each drain pipe to control the upstream water level at a fixed height; the downstream drain pipe is a hose, the height of which can be adjusted arbitrarily, forming a U-shaped pipe with the downstream water tank to control the downstream water level. A crack is provided at the highest point of the drain pipe to connect with the atmosphere to prevent siphoning. The structural design of the monitoring well of the present invention can be layered sampling in one monitoring well, realizing the characterization of the three-dimensional spatiotemporal distribution of the pollution plume. The pollution plume refers to the migration of pollutants in the environmental medium, including convection diffusion, mechanical diffusion and molecular diffusion. Under the joint action of these, the distribution of pollutants is often in the shape of a band radiating from the discharge point. At the same time, the sealed monitoring wellhead and the sampling tube with a three-way valve simplify the monitoring process, and the well can be washed and sampled using a needle-free syringe, which minimizes the volatilization loss of volatile pollutants and improves the monitoring accuracy.

[0018] In the present invention, preferably, the surface of the water filter plate is densely covered with small holes, and water can enter and exit the sand box through the small holes of the water filter plate. At the same time, the small holes block the sand and soil to prevent collapse and outflow.

[0019] In the present invention, preferably, the monitoring wells are evenly distributed in the sand box and arranged horizontally in multiple rows, and the number of the monitoring wells is 15-18.

[0020] In the present invention, preferably, the upstream water inlet pipe is installed with a flow meter. The flow meter can better control the water volume of the upstream water tank.

[0021] Specifically, a sealing cover is provided on the top of the sand box, and the sealing cover can be opened and closed.

[0022] In the present invention, preferably, the first injection well is located in the middle of the sand box near the upstream water tank, and the remaining injection wells are arranged in multiple rows in a horizontal direction in the sand box. The setting and position arrangement of multiple injection wells enable the simulation device of the present invention to be used in a variety of application scenarios. The injection wells in the present invention can be used as injection wells, pollution injection wells, water level monitoring wells, and pumping wells.

[0023] Specifically, the well pipe wall of the injection well is entirely a screen pipe structure below the water level, and a well cover is connected to the top of the well.

[0024] Specifically, the permeable reaction wall is arranged on a side close to the downstream water tank, and the permeable reaction wall is filled with reactive medium. The permeable reaction wall includes a permeable reaction grid.

[0025] Specifically, the wastewater recovery and treatment device recovers the clean water obtained after the wastewater treatment to the liquid supply device through a peristaltic pump.

[0026] The multifunctional groundwater pollution diffusion and in-situ remediation simulation device described in the present invention is used to simulate the migration and adsorption of pollutants in an aquifer medium, and is used to study the remediation effects of groundwater in-situ injection technology, permeable reaction wall technology, and hydraulic regulation technology on contaminated groundwater.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) The device can flexibly and quickly adjust the downstream water level height and the upstream and downstream water level difference, which is conducive to stabilizing the flow field control.

[0029] (2) This device can simulate different pollution scenarios. By adding pollutants into the injection well, the migration, diffusion, and adsorption of pollutants in groundwater can be simulated. By injecting prepared contaminated groundwater solutions into the upstream water tank, a uniform and stable pollution environment can be simulated, which is convenient for evaluating the impact range and remediation effect of the remediation technology.

[0030] (3) This device can perform stratified sampling in one monitoring well, achieving the characterization of the three-dimensional spatial and temporal distribution of the pollution plume. At the same time, the sealed monitoring wellhead and the sampling tube with a three-way valve simplify the monitoring process, and the well can be washed and sampled using a needle-free syringe, which minimizes the volatilization loss of volatile pollutants and improves the monitoring accuracy.

[0031] (4) This device can simulate the remediation effects of various remediation technologies or combined technologies on pollutants, such as in-situ injection technology and permeable reactive wall technology.

[0032] (5) This device can be used to carry out pumping experiments, monitor the water level changes at various points through water level monitoring wells, characterize precipitation funnels, and determine the impact range.

[0033] (6) This device simulates the natural flow field of groundwater and superimposes artificial hydraulic regulation to control the pollution plume and accelerate the migration of effective components of the remediation agent.

[0034] (7) The downstream of this device is equipped with a wastewater treatment and recovery device. The complete simulation system can achieve zero pollution discharge while meeting the needs of groundwater research. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a side view of the multifunctional groundwater pollution diffusion and in-situ remediation simulation device of the present invention.

[0036] Figure 2 It is a schematic diagram of the sand box well layout points in the present invention.

[0037] Figure 3 It is a structural schematic diagram of the water filter plate in the present invention.

[0038] Figure 4 It is a schematic diagram of the structure of the monitoring well of the present invention.

[0039] Figure 5 It is a schematic structural diagram of the injection well of the present invention.

[0040] Figure 6 This is a schematic diagram of the sand box structure dimensions when used as an example in a specific application of the present invention.

[0041] Figure 7 This is a schematic diagram of the sand box well layout points when using the present invention as a specific example.

[0042] Figure 8 This is the benzene distribution diagram of 2# sand box.

[0043] Fig. 9 This is the benzene distribution diagram of 3# sand box.

[0044] Fig.10 This is the benzene distribution diagram of 4# sand box.

[0045] Fig.11 This is the water level change diagram before and after hydraulic regulation of 4# sand box; a: before regulation, b: after regulation.

[0046] in,

[0047] 1—sand box;

[0048] 2—Filling medium: It can be any type of sand to simulate the aeration zone and aquifer;

[0049] 3—Monitoring well; screens 31 and cement 32 are provided at different depths. The cement seals and blocks each screen to achieve layered monitoring. The well contains multiple sampling tubes 33, which go directly from the wellhead to the screen layer. The cement 32 in the well fixes the sampling tubes 33. A three-way valve 34 is provided on the top of the sampling tube 33;

[0050] 4—injection well; the well pipe wall below the water level is all screen pipe structure, among which 41 is the first injection well, 42 is the first row of injection wells, and 43 is the remaining rows of injection wells;

[0051] 5—Water filter board; the surface is densely covered with small holes, water can enter and exit the sand box through the water filter board, while blocking the sand and soil to prevent collapse and outflow;

[0052] 6—Upstream drain pipe; water in the upstream tank that is higher than the pipe mouth can flow back through the upstream drain pipe;

[0053] 7—Valve; controls the opening and closing of each upstream drainage pipe to control the upstream water level at a fixed height;

[0054] 8—liquid preparation tank;

[0055] 9—water pump;

[0056] 10—upstream water inlet pipe;

[0057] 11—Flow meter;

[0058] 12—permeable reactive wall;

[0059] 13—Reactive media;

[0060] 14—Downstream drainage pipe: It is a soft hose with adjustable height, forming a U-shaped pipe with the downstream water tank to control the downstream water level. A crack is provided at the highest point of the downstream drainage pipe to connect with the atmosphere to prevent siphoning.

[0061] 15—Wastewater recovery and treatment device; according to the pollutants in the device, activated carbon, zero-valent iron, ion reaction resin and other adsorbents are filled in a targeted manner to remove pollutants in the wastewater downstream of the sand box;

[0062] 16—upstream flume;

[0063] 17—downstream sink;

[0064] 18—General Manager. DETAILED DESCRIPTION

[0065] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and drawings, but the protection scope of the present invention is not limited to the embodiments.

[0066] Example 1

[0067] like Figure 1 As shown,

[0068] A multifunctional groundwater pollution diffusion and in-situ remediation simulation device comprises a device body, a liquid supply device and a wastewater recovery and treatment device 15.

[0069] The device body includes an upstream water tank 16, a sand box 1 and a downstream water tank 17 which are connected in sequence. The sand box 1 is filled with a filling medium 2. The water inlet side of the sand box 1 is connected to the upstream water tank 16 through a water filter plate 5, and the water outlet side of the sand box 1 is connected to the downstream water tank 17 through a water filter plate 5. A sealing cover is provided on the top of the sand box 1, and the sealing cover can be opened and closed.

[0070] The liquid supply device is composed of a liquid distribution tank 8, a water pump 9, an upstream water inlet pipe 10 and an upstream overflow pipe. The upstream water inlet pipe 10 is connected to the top of the upstream water tank 16, and a flow meter 11 is installed on the upstream water inlet pipe 10. The water pump 9 allows the liquid in the liquid distribution tank 8 to enter the upstream water tank 16 through the upstream water inlet pipe 10. The upstream overflow pipe includes a main pipe 18, and the main pipe 18 is connected to a plurality of upstream drainage pipes 6 of different heights. The upstream drainage pipes 6 of different heights are connected to one side of the upstream water tank 16, and a valve 7 is installed on the upstream drainage pipe 6.

[0071] A hole is provided at the bottom of the downstream water tank 17, and the hole is sealed and connected to the downstream drainage pipe 14; the downstream drainage pipe 14 is a hose, forming a U-tube effect with the downstream water tank 17, and a crack is provided at the highest point of the downstream drainage pipe 14; the water outlet of the downstream drainage pipe 14 is located above the wastewater recovery and treatment device 15; the wastewater recovery and treatment device 15 recovers the clean water obtained after the wastewater treatment to the liquid supply device through a peristaltic pump.

[0072] like Figure 1 , Figure 2As shown, a permeable reaction wall 12, 15 monitoring wells 3 and 15 injection wells 4 are vertically arranged in the sand box 1; the permeable reaction wall 12 is arranged on the side close to the downstream water tank 17, and the permeable reaction wall 12 is filled with reactive medium 13. The 15 monitoring wells are divided into 5 columns according to 3 in a column and evenly distributed in the sand box. The injection wells include a first injection well 41, which is located in the middle of the sand box close to the upstream water tank, and the remaining injection wells are arranged in multiple columns horizontally in the sand box, specifically distributed in the left part of the sand box close to the upstream water tank, the middle part of the sand box and the right part of the sand box close to the downstream water tank, wherein the first column of injection wells 42, a total of 5 injection wells, can be used as repair agent injection wells, and the remaining columns of injection wells 43 have 3 in each column. The arrangement and position arrangement of multiple injection wells of the present invention enable the simulation device of the present invention to be used in a variety of application scenarios. The injection wells in the present invention can be used as injection wells, pollution injection wells, water level monitoring wells and pumping wells.

[0073] like Figure 3 As shown, the surface of the water filter plate 5 is densely covered with small holes, and water can enter and exit the sand box through the small holes of the water filter plate. At the same time, the small holes block the sand and soil to prevent collapse and outflow.

[0074] like Figure 4 As shown, a plurality of screen tubes 31 and cement 32 are longitudinally arranged in the monitoring well 3, the screen tubes 31 and cement 32 are arranged alternately, and the cement 32 seals and blocks each screen tube 31; the monitoring well 3 contains a plurality of sampling tubes 33, the sampling tubes 33 are directly connected to the screen tubes from the wellhead, a three-way valve 34 is provided on the top of the sampling tube, each sampling tube is directly connected to a different screen tube, and the cement fixes the sampling tube;

[0075] like Figure 5 As shown, the well pipe wall of the injection well is entirely a screen pipe structure below the water level, and a well cover is connected to the top of the well.

[0076] Specific usage examples

[0077] Build 4 open-top iron boxes, numbered 1# to 4#. The internal dimensions of the iron boxes are: length 5898mm / width 2352mm / height 2393mm. The bottom of the box is designed according to the container, with a reserved groove for easy forklift transportation. The four sides of the box are reinforced horizontally and vertically to meet the pressure requirements of holding a full box of water and soil.

[0078] On one side of the box with a width of 2352mm and a height of 2393mm, 10 holes are drilled in a row from top to bottom. The hole diameter is 100mm, and the center distance between two adjacent holes is 20cm. A ton barrel valve is installed in each hole as an upstream drainage pipe; a round hole with a hole diameter of 100mm is drilled at the bottom of the other side to install a downstream drainage pipe. A baffle is added at each of the ABCD and abcd surfaces of the box. The baffle is a steel plate with a thickness of 0.5-1cm. The steel plate is perforated with a hole diameter of 2-3cm. The hole arrangement method is as follows Figure 6 As shown. The baffle is reinforced with internal support. The distance between the baffle and the outer side is 300mm.

[0079] The filling media in the four sand boxes are pure sand (1#), pure sand and red soil mixed in a ratio of 3:1 (2#~4#), and the height of the sand is 2m. The pollution injection wells / injection wells, remediation agent injection wells, water quality monitoring wells, water level monitoring wells, and permeable reaction grids of the four iron boxes are arranged as follows: Figure 7 As shown. All types of wells are made of PVC pipes, with a length of 2.3m and a diameter of 5cm. Among them, the pollution addition well / injection well, repair agent addition well, and water level monitoring well have the same structure. The bottom of the well pipe is cut into a screen tube shape with a cutting machine or electric drill. The screen tube structure is 2m high and covered with a 100-mesh nylon mesh to prevent sand and soil from silting up the well pipe; the bottom of the water quality monitoring well is 3 screen tube structures and cement partitions interlayered. The height of the screen tube and the cement partition is 20cm. PE material sampling tubes are arranged in each layer of the screen tube. The top of the sampling tube is higher than the wellhead and is equipped with a three-way valve (the structure is shown in the figure). Figure 4 , Figure 5 The permeable reaction grid is supported by two perforated baffle steel plates, with a spacing of 15 cm between the two plates, which can be filled with various active materials according to experimental needs.

[0080] The experimental method is to open the upstream water pump, close the valves of the lower 5 upstream drainage pipes, and keep the liquid level at the bottom of the 6th upstream drainage pipe with the valve open, that is, 1m high. Excess water can be discharged into the liquid distribution tank through the upstream drainage pipe. The highest point of the downstream drainage pipe is fixed at 0.9m. After two days of operation, the simulated groundwater flow field in the device has reached stability. After measurement, the permeability coefficients of various sandy soil media are as shown in the following table.

[0081] Table 1

[0082] Sand box 1# 2# 3# 4# Media Type Pure sand Sand and soil 3:1 mixture Sand and soil 3:1 mixture Sand and soil 3:1 mixture Upstream water level (cm) 100 100 100 100 Downstream water depth (cm) 90 90 90 90 Water flow rate (mL / s) 8.42 2.39 2.34 2.38 Permeability coefficient (m / d) 34.21 9.73 9.51 9.66

[0083] After the flow field reaches stability, 3L of benzene solution with a concentration of 600mg / L is injected into the pollution injection wells of the 2#, 3#, and 4# sand boxes to simulate the diffusion, migration, and remediation of point source pollution. Among them, 3L of Pseudomonas bacteria and 2kg of calcium peroxide slow-release oxidant are respectively added to the remediation agent injection wells of the 3# and 4# sand boxes, and calcium peroxide slow-release oxidant and biochar are filled in the permeable reaction grids of the 3# and 4# sand boxes. Hydraulic regulation is carried out in the 4# sand box, that is, groundwater is extracted from the pumping well at a flow rate of 193ml / min and injected into the upstream injection well of the sand box to control the migration range of benzene, accelerate the flow of groundwater, and promote full contact and reaction between the remediation agent and the pollutant. Activated carbon and biochar are filled in the wastewater recovery and treatment device. The benzene content of the filtered wastewater is determined to be lower than the detection limit (0.0014mg / L), so it is injected into the liquid distribution tank through a peristaltic pump for recycling.

[0084] After the addition, the water level in the water level monitoring wells of the three sand boxes was monitored with a water level gauge at a certain time interval. Samples were taken from the water quality monitoring wells of the three sand boxes, stored in 40 ml brown sample bottles, and analyzed by the gas chromatography-mass spectrometer in the laboratory. The temporal and spatial distribution of benzene in the three sand boxes is shown in Figure 1. Figure 8-10 As shown, Figure 8 is the temporal and spatial distribution law of benzene in the 2# sand box, Fig. 9 is the temporal and spatial distribution law of benzene in the 3# sand box, Fig.10 The temporal and spatial distribution of benzene in the 4# sand box. The water level height difference before and after hydraulic regulation is as follows: Fig.11 shown.

[0085] According to the disclosure and teaching of the above description, those skilled in the art to which the present invention belongs may also make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the invention should also fall within the scope of protection of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for the convenience of description and do not constitute any limitation to the present invention.

Claims

1. A multifunctional groundwater pollution diffusion and in-situ remediation simulation device, characterized in that: It includes a device body, a liquid supply device and a wastewater recovery and treatment device; The device body comprises an upstream water tank, a sand box and a downstream water tank which are connected in sequence, the sand box is filled with a filling medium, the water inlet side of the sand box is connected to the upstream water tank through a water filter plate, and the water outlet side of the sand box is connected to the downstream water tank through a water filter plate; The liquid supply device is composed of a liquid distribution tank, a water pump, an upstream water inlet pipe and an upstream overflow pipe. The upstream water inlet pipe is connected to the top of the upstream water tank. The water pump allows the liquid in the liquid distribution tank to enter the upstream water tank through the upstream water inlet pipe. The upstream overflow pipe includes a main pipe, which is connected to a plurality of upstream drainage pipes of different heights. The upstream drainage pipes of different heights are respectively connected to a side surface of the upstream water tank and the liquid distribution tank. A valve is installed on the upstream drainage pipe. A hole is provided at the bottom of the downstream water tank, and a downstream drainage pipe is sealed and connected to the hole; the downstream drainage pipe is a hose, forming a U-shaped pipe effect with the downstream water tank, and a crack is provided at the highest point of the downstream drainage pipe; the water outlet of the downstream drainage pipe is located above the wastewater recovery and treatment device, and the wastewater recovery and treatment device recovers the clean water obtained after the wastewater treatment to the liquid supply device through a peristaltic pump; A permeable reaction wall, a plurality of monitoring wells and a plurality of injection wells are vertically arranged in the sand box; The permeable reaction wall is arranged on a side close to the downstream water tank, the permeable reaction wall comprises a permeable reaction grid, and the permeable reaction wall is filled with a reactive medium; A plurality of screen tubes and cement are arranged longitudinally in the monitoring well, the screen tubes and cement are arranged alternately, and the cement seals and blocks each screen tube; a plurality of sampling tubes are contained in the monitoring well, the sampling tubes are directly connected to the screen tubes from the wellhead, a three-way valve is arranged on the top of the sampling tubes, each sampling tube is directly connected to a different screen tube, and the cement fixes the sampling tubes; The several injection wells include a first injection well, which is located in the middle of the sand box near the upstream water tank, and the remaining injection wells are evenly distributed in the left part of the sand box near the upstream water tank, the middle part of the sand box and the right part of the sand box near the downstream water tank.

2. The multifunctional groundwater pollution diffusion and in-situ remediation simulation device according to claim 1 is characterized in that: The surface of the water filter plate is densely covered with small holes, and water can enter and exit the sand box through the small holes of the water filter plate, while the small holes block the sand and soil.

3. The multifunctional groundwater pollution diffusion and in-situ remediation simulation device according to claim 1 is characterized in that: The monitoring wells are evenly distributed in the sand box and arranged horizontally in multiple rows. The number of the monitoring wells is 15-18.

4. The multifunctional groundwater pollution diffusion and in-situ remediation simulation device according to claim 1 is characterized in that: The upstream water inlet pipe is equipped with a flow meter.

5. The multifunctional groundwater pollution diffusion and in-situ remediation simulation device according to claim 1 is characterized in that: A sealing cover is provided on the top of the sand box, and the sealing cover can be opened and closed.

6. The multifunctional groundwater pollution diffusion and in-situ remediation simulation device according to claim 1 is characterized in that: The first injection well is located in the middle of the sand box near the upstream water tank, and the remaining injection wells are arranged in multiple rows horizontally in the sand box.

7. The multifunctional groundwater pollution diffusion and in-situ remediation simulation device according to claim 1 is characterized in that: The well pipe wall of the injection well is entirely a screen pipe structure below the water level, and a well cover is connected to the top of the well.

8. The multifunctional groundwater pollution diffusion and in-situ remediation simulation device described in any one of claims 1 to 7 is used to simulate the migration and adsorption of pollutants in aquifer media, and is used to study the remediation effects of groundwater in-situ injection technology, permeable reaction wall technology, and hydraulic regulation technology on contaminated groundwater.

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