CN105234163A - Simulating device for soil vapor extraction technique - Google Patents

Abstract

A soil gas phase extraction technology simulation device, including a three-dimensional test sand box, a gas phase extraction device connected to the sand box, and a biochar immobilized bacterial agent adding device. The gas phase extraction device includes an air jet pump, a flow meter, an air jet well, An extraction well, an activated carbon filter and a vacuum pump, the biochar immobilized bacterial agent addition device includes a pressurized injection pump and an injection well. The invention also provides a biochar immobilized bacteria agent adding device and a box cover of a three-dimensional test sand box. The device of the present invention can carry out the soil gas-phase extraction test under homogeneous or heterogeneous soil layer conditions, biochar-immobilized bacterial agent degradation test and biochar-immobilized bacterial agent-enhanced simulation test of gas-phase extraction; during the test process It can monitor various parameters in real time, mainly including aeration flow rate, extraction flow rate and vacuum degree, etc.; at the same time, it can also sample and measure soil samples or gas samples at different positions in the soil layer at different stages of the test to determine the pollution site. The biochar-immobilized bacterial agent strengthens the remediation effect of soil gas phase extraction technology.

Description

Soil gas phase extraction technology simulation device

technical field

The invention relates to the technical field of soil treatment, and more particularly to an experimental device for soil gas phase extraction, in particular to a simulation device for research on the removal of VOCs by soil gas phase extraction technology.

Background technique

Soil vapor phase extraction technology is a soil remediation technology for volatile organic compounds, which is simple to operate, low in cost and does not damage the soil structure. However, there are some shortcomings in the soil gas phase extraction technology. There is a tailing period in its application. The concentration of volatile and semi-volatile pollutants in the initial soil drops rapidly. As time goes by, the residual pollutants in the soil do not directly contact with the incoming gas. , but slowly diffused into the soil pores through the water film, and then discharged out of the system with the airflow, the contribution of volatilization to remove pollutants gradually weakened, the concentration of pollutants in the soil basically no longer decreased, and the ventilation repair entered the late stage of tailing.

Some scholars proposed to combine soil gas phase extraction technology with high-efficiency bacterial degradation. The results show that the addition of bacterial agents is very effective for the removal of residual VOCs in soil. However, the current indoor simulation experiments mostly stay at the research stage of small soil columns. How to add Efficient degradation of bacteria and effective verification of their effects are the difficulties of this type of experiment.

Contents of the invention

Based on the above technical problems, an object of the present invention is to provide a biochar immobilized bacterial agent adding device, another object of the present invention is to provide a box cover for a three-dimensional test sand box, and another object of the present invention is to provide a A soil gas phase extraction technology simulation device.

In order to achieve the above object, as one aspect of the present invention, the present invention provides a biochar immobilized bacterial agent adding device, comprising a pressurized injection pump and an injection well connected in series, wherein the top of the injection well is provided with a biochar immobilized The sterilizing agent addition hole, the bottom of the injection well is connected to the helical drill bit, the diameter of the helical drill bit is larger than the diameter of the injection well, and there are several uniformly distributed injection holes above the helical drill bit.

As another aspect of the present invention, the present invention also provides a box cover of a three-dimensional test sand box, the middle part of the box cover is an extraction well hole, and several gas sampling holes are distributed around the extraction well hole, wherein The arrangement of the several gas sampling holes is distributed in a cross shape with the extraction well hole as the center.

As another aspect of the present invention, the present invention also provides a soil gas phase extraction technology simulation device, including a three-dimensional test sand box, a gas phase extraction device and a sampling device connected in series with the three-dimensional test sand box, wherein the three-dimensional test sand box The test sand box includes a sand box main body, a pollutant adding device and a pipeline, a soil sampling hole arranged on the side of the sand box main body, a box cover arranged on the top of the sand box main body, and the arrangement of the pollutant adding device and pipeline The position is used to add the pollutants used for the test into the inside of the main body of the sand box according to actual needs.

Compared with the prior art, the present invention has the following advantages:

(1) The simulation device of the present invention can simulate situations such as homogeneous soil layers and heterogeneous soil layers through different combinations of filled soil samples, and on this basis, perform biochar fixation under various complex soil layer conditions Bacterial agent enhanced gas phase extraction technology simulation test;

(2) The simulation device of the present invention can carry out soil gas phase extraction experiment respectively, biochar immobilized bacterial agent addition experiment or two experiments are carried out in combination;

(3) The simulation device of the present invention is provided with a biochar immobilized bacterial agent adding device, which can be rotated into the polluted soil layer by using the spiral drill bit at the bottom of the injection well. Through the injection hole on the upper part of the drill bit, the liquid biochar-immobilized bacterial agent is injected into the contaminated soil interface by means of high-pressure injection using a pressurized injection pump, thereby solving the problem of combining soil gas phase extraction technology with efficient degradation bacteria.

Description of drawings

Fig. 1 is soil gas phase extraction technology simulation device of the present invention;

Fig. 2 is the schematic diagram of the design of the lid of the three-dimensional sand box;

Fig. 3 is the design schematic diagram of biochar immobilized bacterial agent adding device of the present invention;

Fig. 4 is a schematic diagram of the design of the drill bit part of the present invention.

The reference signs of main components in the accompanying drawings are explained as follows:

1. Jet pump; 2. Connecting pipeline; 3. Flow meter; 4. Sand box; 5. Pollutant adding device and pipeline; 6. Jet well; 7. Pressurized injection pump; 8. Extraction well; 9. Pipeline ;10, activated carbon filter; 11, vacuum pump; 12, soil sampling hole; 13, injection well; 14, sand box cover; 15, gas sampling hole; 16, extraction well hole; 17, injection hole; 18, spiral Drill bit; 19. Biochar immobilized bacterial agent addition hole; 20. Injection hole protection cover; 21. Retractable interface.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

The invention discloses a soil gas phase extraction technology simulation device, which expands the capacity of the existing soil gas phase extraction device in the laboratory to a certain extent, simulates the actual site as much as possible, and avoids the small-scale soil column experiment process. The side wall effect and the immobilized bacterial agent adding device are combined into the SVE simulation experiment. When the SVE experiment enters the tailing stage, the effective degrading agent is injected into the experimental soil through the immobilized agent adding device, so as to quantitatively judge the removal effect of the immobilized agent on VOCs in the tailing stage, and verify the effectiveness of the agent injection device .

More specifically, the soil gas phase extraction technology simulation device of the present invention combines the soil gas phase extraction technology with the degradation of high-efficiency bacteria to simulate the restoration process, combines high-efficiency bacteria with biochar to form a liquid biochar immobilized bacterial agent, and utilizes The biochar-immobilized bacterial agent adding device is injected under high pressure into the contaminated soil in the soil gas phase extraction repair tailing stage, so as to quantitatively judge the removal effect of the immobilized bacterial agent on VOCs in the tailing stage.

The soil gas phase extraction technology simulation device of the present invention comprises a three-dimensional test sand box, a gas phase extraction device and a sampling device connected in series with the sand box. The three-dimensional test sand box includes sand box, pollutant adding device and pipeline, soil sampling hole set on the side of the sand box, sand box cover set on the top of the sand box, gas sampling hole and extraction well hole set on the sand box cover .

The gas phase extraction device includes jet pumps, connecting pipes, flowmeters, jet wells, extraction wells, activated carbon filters and vacuum pumps. The devices are connected sequentially as required.

In addition, the soil gas phase extraction technology simulation device of the present invention may also include a biochar-immobilized bacterial agent adding device, and the biochar-immobilized bacterial agent adding device includes a pressurized injection pump and an injection well. The pressurized injection pump is connected with the injection well, and the injection well goes deep into the simulation device through the gas sampling hole on the lid of the sand box. The biochar-immobilized bacterial agent adding device is composed of a pressurized injection pump and injection wells in series, and the number of injection wells can be increased or decreased according to the experimental situation. The bottom of the injection well connected to the pressurized injection pump is connected to the spiral drill bit. The diameter of the drill bit is larger than the diameter of the injection well, and it is connected to the injection hole protection cover to protect the injection hole from being blocked by soil. There are 6 injection holes above the drill bit, separated by two 60°, in the protective cover of the injection hole, evenly distributed on the wall of the injection well pipe, used for pressurized injection of the biochar-immobilized bacterial agent into the soil, the top of the injection well is equipped with a biochar-immobilized bacterial agent adding hole, and The middle part is provided with a retractable interface for adjusting the length of the injection well.

In the following, the present invention will be further specifically explained in conjunction with the drawings and embodiments of the specification.

As shown in Figure 1, the present invention provides a soil gas phase extraction technology simulation device, including a three-dimensional test sand box, a gas phase extraction device connected to the sand box, a biochar immobilized bacterial agent adding device and a sampling device. The three-dimensional test sand box includes a sand box 4, a pollutant adding pipeline 5, a soil sampling hole 12 arranged on one side of the sand box, a sand box cover 14, and a gas sampling hole 15 and an extraction well 16 arranged on the sand box cover. The gas-phase extraction device comprises a jet pump 1 connected in sequence, a connecting pipeline 2, a flow meter 3 and a jet well 6, and an extraction well 8, and the flow meter arranged on the extraction well connects an active carbon filter 10 and a vacuum pump 11 through a pipeline, Form a complete soil gas phase extraction technology device. The biochar immobilized bacterial agent adding device includes a pressurized injection pump 7 and an injection well 13 . The pressurized injection pump 7 is connected with the injection well 13, and the injection well 13 goes deep into the test device through the gas sampling hole 15 on the lid of the sand box.

As shown in Figures 1 and 2, the size of the three-dimensional sand box 4 is 1000mm long, 1000mm high, and 1200mm high, and the material is plexiglass. There are 10 soil sampling holes 12 with a diameter of 40 mm on the side of the sand box, and each pair is separated by 100 mm. In the middle of the sand box cover 14 is an extraction well 16 with a diameter of 60mm. There are 24 gas sampling holes 15 with a diameter of 10 mm distributed in a cross shape. There are 6 gas sampling holes on one side, the spacing between the 5 holes near the extraction well is 50mm, and the spacing of the outermost gas sampling holes is 100mm. The flow rate of jet pump 1 is 10-60L/min, the flow rate of vacuum pump 11 is 10-60L/min, the vacuum degree is less than 30kPa, and the flow rates of the two pumps are adjustable. The measurement range of the flow meter 3 is 0-30L/min. The pressure of the pressurized syringe pump 7 can reach up to 1MPa. The materials of jet well 6, extraction well 8 and connecting pipelines are PVC pipes.

As shown in Figure 3 and Figure 4, the pressurized injection pump 7 of the biochar-immobilized bacterial agent addition device is connected to the injection well 13, and the injection well 13 goes deep into the test device through the gas sampling hole on the sand box cover. The bottom of the injection well 13 is connected with the spiral drill bit 18, which is used for the injection well to rotate into the soil. The diameter of the drill bit is larger than that of the injection well 13, and it is connected with the injection hole protection cover 20 to protect the injection hole from being blocked by the soil. There are 6 injection holes above the drill bit. Holes 17, separated by 60° in pairs, are evenly distributed on the wall of the injection well pipe in the injection hole protective cover 20, and are used for pressurized injection of biochar-immobilized bacterial agents into the soil. There are 6 injection holes 17 at 10 cm above the drill bit, and they are evenly distributed on the wall of the injection well pipe at a distance of 60°. They are used for pressurized injection of biochar-immobilized bacterial agents into the soil. In addition, a retractable interface 21 is provided in the middle of the injection well 13 for adjusting the length of the injection well 13 . The materials of the injection well 13 and the helical drill bit 18 are all stainless steel.

When the device of the present invention is in use:

(1) After assembling the three-dimensional test sand box, the gas phase extraction device, the biochar-immobilized bacterial agent adding device and the sampling device, use the pollutant adding pipe 5 to add pollutants. First, use the gas phase extraction device to extract pollutants, and use the gas sampling hole to detect the concentration of pollutants. When the concentration of pollutants no longer changes, the soil gas phase extraction technology reaches the tailing period, and then use biochar to immobilize the bacterial agent Adding device to add high-efficiency degrading bacteria, quantitatively judge the removal effect of immobilized bacterial agent on VOCs in the tailing stage, and verify the effectiveness of the bacterial agent injection device.

(2) When carrying out the gas phase extraction test, the gas sampling hole 15 designed by the lid 14 of the sand box can be used to set a plurality of gas injection wells, and the gas injection wells can be deep into the sand box in different directions, or at different depths. Make a jet. During the test, parameters such as jet pressure, jet flow and extraction flow can be monitored, and at different stages of the test, gas sampling holes can be used to sample at different positions in the soil layer for quantitative analysis.

(3) When carrying out the carbon-immobilized bacterial agent addition test, the gas sampling hole 15 designed by the lid 14 of the sand box can be used to select different positions and depths for pressurized injection of the high-efficiency bacterial agent. Use the helical drill bit 18 at the bottom of the injection well 13 to rotate into the soil, and adjust the length of the injection well 13 in combination with the telescopic interface 21. There are 6 injection holes above the drill bit, which are 60° apart and evenly distributed on the wall of the injection well. Combined with pressurized injection Pump 7 is used for biochar immobilized bacterial agent injection. At the same time, at different stages of the test, the soil sampling holes can be used to take samples at different positions of the soil layer for quantitative analysis.

Through actual use, the soil gas phase extraction technology simulation device of the present invention can carry out the soil gas phase extraction test under homogeneous or heterogeneous soil layer conditions, biochar immobilized bacterial agent degradation test and biochar immobilized bacterial agent enhanced gas phase Extraction simulation test; during the test process, various parameters can be monitored in real time, mainly including aeration flow, extraction flow and vacuum degree; at the same time, soil samples at different positions in the soil layer or The gas samples were sampled and measured to determine the remediation effect of the biochar-immobilized bacterial agent-enhanced soil gas-phase extraction technology for the polluted site.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the present invention. Within the spirit and principles of the present invention, any modifications, equivalent replacements, improvements, etc., shall be included in the protection scope of the present invention.

Claims (10)

1. A biochar immobilized bacterial agent adding device, comprising a pressurized injection pump and an injection well connected in series, wherein the top of the injection well is provided with a biochar immobilized bacterial agent adding hole, and the bottom of the injection well is connected with a spiral The drill bit is connected, the diameter of the helical drill bit is larger than the diameter of the injection well, and there are several uniformly distributed injection holes above the helical drill bit. 2. The biochar-immobilized bacterial agent adding device as claimed in claim 1, wherein the upper end of the helical drill bit is connected with the injection hole protective cover to protect the injection hole from being blocked by soil. 3. The biochar-immobilized bacterial agent adding device according to claim 1, wherein a retractable interface is provided in the middle of the injection well for adjusting the length of the injection well. 4. A case cover of a three-dimensional test sand box, the middle part of the case cover is an extraction well hole, and several gas sampling holes are distributed around the extraction well hole, wherein the arrangement of the several gas sampling holes is as follows: The above-mentioned extraction wells are distributed in a cross shape with the center as the center. 5. A soil gas phase extraction technology simulation device, comprising a three-dimensional test sand box, a gas phase extraction device and a sampling device connected in series with the three-dimensional test sand box, wherein the three-dimensional test sand box includes a sand box main body, pollutants added device and pipeline, the soil sampling hole that is arranged on the side of the sand box main body, the box cover that is arranged on the top of the sand box main body, the setting position of the pollutant adding device and the pipeline is used to pollute the test with substance added to the inside of the sand box body. 6. The soil gas phase extraction technology simulation device as claimed in claim 5, wherein said gas phase extraction device comprises connecting pipes, jet wells, extraction wells and vacuum pumps assembled and connected according to actual use needs. 7. The soil gas phase extraction technology simulation device as claimed in claim 5, wherein said soil gas phase extraction technology simulation device also comprises the biochar immobilized bacterial agent adding device as described in any one of claims 1 to 3, The biochar immobilized bacterial agent adding device goes deep into the interior of the sand box main body through the gas sampling hole on the box cover at the top of the sand box main body. 8. The soil vapor phase extraction technology simulation device as claimed in claim 7, wherein there are 6 injection holes above the auger bit, and each pair is separated by 60°. 9. The soil gas phase extraction technology simulation device as claimed in claim 5, wherein the case cover on the top of the sand box main body adopts the case cover of the three-dimensional test sand box according to claim 4, and the number of the gas sampling holes for 24. 10. The soil gas phase extraction technology simulation device as claimed in claim 5, wherein the material of the three-dimensional test sand box is plexiglass, and there are 10 soil sampling holes on the side of the three-dimensional test sand box.