Mobile soil remediation device.

Abstract

A mobile soil remediation device (10) is proposed for carrying out tests on a site to be remediated, the device (10) comprising: an air extraction unit (12) adapted to extract air from an extraction well (PV1), an air injection unit (14) adapted to inject air into an injection well (PS); and a control unit (16) configured to control an air intake flow rate in the extraction well (PV1) and / or an air injection flow rate in the injection well (PS) and to record data measured by at least one sensor provided in the extraction well (PV1), in the injection well (PS) and / or in at least one control structure (PV2, PV3, D, PZA, PZB), the control structure (PV2, PV3, D, PZA, PZB) being located at a distance from the extraction well (PV1) or the injection well (PS). Abstract figure: Figure 3

Description

Title of the invention: Mobile soil remediation device. technical field

[0001] This disclosure relates to the field of soil remediation. More specifically, this disclosure relates to a mobile device for conducting soil remediation tests. This disclosure describes a method for implementing soil remediation tests. Previous technique

[0002] Examples of techniques for treating soils polluted by volatile compounds include venting of the unsaturated zone and in-situ sparging. Venting involves extracting volatile pollutants by depressurizing the unsaturated zone from an extraction well. Sparging involves injecting air into the groundwater via an injection well to promote the volatilization of volatile pollutants, which then flow out of the extraction well. Ventilation and sparging can also be combined.

[0003] It has been proposed to conduct laboratory tests to determine the most suitable remediation techniques for the soil to be treated. However, such tests rely on insufficient data, such as soil geology and hydrogeology. The extent and characteristics of the soil pollution remain poorly understood or unknown during these tests. Furthermore, such tests do not take into account the size and accessibility of the site to be treated. Thus, the remediation techniques implemented following these tests are ineffective and can lead to a significant increase in the cost of remediation work, as well as generate nuisances for nearby residents.

[0004] Furthermore, during the implementation of on-site remediation techniques, the control of the flow rates of air extracted and / or injected into the ground, as well as the control of temperature and pressure, is conventionally carried out by opening wells and taking a manual measurement. However, such a measurement is imprecise and unreliable. It is therefore difficult to acquire accurate data on the effectiveness of the remediation technique implemented. Summary

[0005] This disclosure improves the situation.

[0006] A mobile soil remediation device is proposed for conducting tests on a site to be remediated, the device comprising: - an air extraction unit suitable for extracting air from an extraction well; - an air injection unit adapted to inject air into an injection well; and; - a control unit configured to control an air suction flow rate in the extraction well and / or an air injection flow rate in the injection well and to record data measured by at least one sensor provided in the extraction well, in the injection well and / or in at least one control structure, the control structure being remote from the extraction well or the injection well.

[0007] Such a mobile unit allows for data acquisition directly on site. Tests can be programmed and carried out to characterize soils, validate the effectiveness of a planned technique, and / or perform preliminary sizing for large-scale treatment. It should be noted that the proposed device can be used for a ventilation test, a splash test, or a combined ventilation and splash test.

[0008] Data recording eliminates measurement uncertainties generally caused by opening wells during manual measurements. It allows for a much more reliable determination of the interactions between the soil and the wells.

[0009] The features described in the following paragraphs may optionally be implemented independently of each other or in combination with each other.

[0010] The measured data are at least one of: an injected air flow rate, an extracted air flow rate, a temperature, a pressure, a depression and a gas concentration.

[0011] The measured data are then relevant for acquiring accurate and reliable information on the site to be decontaminated in order to characterize the soils and select an appropriate decontamination strategy.

[0012] The mobile unit further includes a trailer on which is mounted the suction unit, the injection unit and the control unit.

[0013] The mobile unit can easily be transported and installed on site, without the need for significant work or manpower.

[0014] The suction unit includes a turbine with a variable suction capacity of up to about 85 m3 / h and a maximum relative depression of about -210 mbar.

[0015] The suction unit includes at least one carbon filter with a capacity of approximately 80 L.

[0016] The suction unit is thus adapted to collect relevant measurements, for example for large-scale processing, without compromising the mobility of the device.

[0017] The injection unit includes a compressor with a modulating blowing capacity of up to approximately 40m3 / h and a maximum relative pressure of 800 mbar.

[0018] The injection unit is thus adapted to collect relevant measurements, for example for large-scale treatment, without compromising the mobility of the device.

[0019] The control unit includes a control panel configured for visualization data reading and recording, selection of aspiration flow rate and / or injection flow rate and test duration.

[0020] The user can then configure a test according to the data they wish to collect. The control unit can then perform the test automatically, without subsequent user intervention. Furthermore, the user can view the effect of the injection or extraction in real time. The test can be continuously monitored by the user. The user can also use and analyze the data recorded following a test.

[0021] The control unit includes a communication device configured to communicate data to a remote interface.

[0022] A user can view the data remotely, for example from an interface. The data can be used by a management center as soon as it is acquired.

[0023] According to another aspect, a method is proposed for carrying out tests of pollution control techniques comprising: - Select an air injection rate in an extraction well and / or an air extraction rate in an injection well and a test duration; - Extract air from the extraction well and / or inject air into the injection well according to the selected flow rate and for the duration of the test; - Record data measured by at least one sensor provided in the extraction well, in the injection well and / or in a control structure, the control structure being remote from the extraction well or the injection well.

[0024] Thus, it is possible to configure a test according to the desired data in order to characterize soils, validate the effectiveness of a planned technique, and perform preliminary sizing before large-scale treatment. The test is implemented automatically, without requiring user intervention. The data can be recorded continuously, automatically, and reliably, eliminating uncertainties related to well opening.

[0025] The air injection rate and / or the extraction rate increases in steps during the duration of the test.

[0026] The stepwise increase allows, in particular, visualization of the optimal flow rate at which the injection or extraction has the greatest radius of influence. The increase is performed automatically, and no user intervention is required. Brief description of the drawings

[0027] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analysis of the accompanying drawings, on which: Fig. 1

[0028] [Fig.1] schematically illustrates the implementation of a method for ventilating a non-saturated zone. Fig. 2

[0029] [Fig.2] schematically illustrates the implementation of a bubbling method in situation. Fig. 3

[0030] [Fig.3] schematically illustrates a top view of a mobile device for carrying out tests on a site to be decontaminated according to one embodiment. Fig. 4

[0031] [Fig.4] schematically illustrates a top view of the device of [Fig.1] during a ventilation test. Fig. 5

[0032] [Fig.5] schematically illustrates a top view of the device of [Fig.1] during a bubbling test. Fig. 6

[0033] [Fig.6] schematically illustrates an example of a control panel that can be implemented in the device of [Fig.1]. Fig. 7

[0034] [Fig.7] schematically illustrates an example of well positioning that can be used by the device in [Fig.1]. Fig. 8

[0035] [Fig.8] schematically illustrates an example of data measured during a ventilation test. Fig. 9

[0036] [Fig.9] schematically illustrates an example of data measured during a test of splashing. Description of the implementation methods

[0037] Figures 1 and 2 schematically illustrate the implementation of unsaturated zone ventilation (“venting”) and in-situ sparging techniques on a site to be remediated. The site to be remediated is polluted, in particular, by volatile components. Volatile components may, for example, be total petroleum hydrocarbons (TPH); semi-volatile organic compounds (VOCs); semi-volatile halogenated organic compounds (SHOVCs); volatile organic compounds (VOCs); and / or volatile organic compounds (VOCs).

[0038] As can be seen in [Fig. 1], the ventilation technique consists of extracting the volatile components located in an unsaturated zone 1000, i.e. the zone between the ground surface 1010 and a water table 1012, by creating a negative pressure in an extraction well 1014 extending into the ground. The negative pressure is generated by a turbine 1016 and causes the polluted air around the extraction well 1014 to be drawn in. The drawn-in air can pass through a de-evaporator 1020 to retain the droplets present in the air, and through filters 1022 to treat the polluted air before its release into the atmosphere.

[0039] Referring to [Fig. 2], the bubbling technique consists of extracting volatile components located in the groundwater 1012. A compressor 1024 injects pressurized air into an injection well 1026 and into the groundwater 1012. The air propagating through the groundwater 1012 rises to the surface, carrying a load of pollutants. The polluted air is then discharged through the extraction well 1014 (or several extraction wells). The extracted air can also circulate through the demister and filters as described above.

[0040] It should be noted that ventilation and bubbling techniques can be combined. In this case, air is simultaneously injected into the injection well 1026 and drawn from the extraction well 1014.

[0041] Figure 3 schematically illustrates a top view of a mobile device 10 for conducting tests of ventilation, squirting, and combined ventilation-squirting techniques. The purpose of the tests is to verify the feasibility of a planned technique and to perform preliminary sizing of the technique for large-scale treatment as illustrated in Figures 1 and 2.

[0042] The mobile device 10 essentially comprises an air suction unit 12, an air injection unit 14 and a control unit 16.

[0043] The suction, injection, and control units 12, 14, and 16 are mounted on a trailer 18. The mobile device 10 can then be easily moved to a site for in-situ testing. The on-site tests do not require significant setup or labor. In the illustrated example, the trailer 18 includes a right wheel 54, a left wheel 56, and a drawbar 52. The trailer can be towed by any vehicle and can travel on the standard road network without requiring any special precautions or special transport regulations.

[0044] The suction unit 12 essentially comprises, as illustrated, a demister 20, two activated carbon filters 22, a dust filter 24, and a turbine 26. The suction unit 12 is connected to the extraction well PV1 from which polluted air is drawn. As shown in [Fig. 4], air extracted from the extraction well PV1 enters the suction unit 12 and passes, in that order, through the demister 20, the carbon filter(s) 22, the dust filter 24, and the turbine 26. The air extracted from the extraction well PV1 is then treated at the outlet of the turbine 26 and can be released into the environment.

[0045] Here, the suction capacity of the turbine 26 is adjustable up to approximately 85 m³ / h with a maximum vacuum of approximately -210 bar (relative to atmospheric pressure). Such a suction capacity allows for satisfactory ventilation and ventilation-bubbling tests for future larger-scale implementation, while remaining compact enough to be placed on the trailer 18.

[0046] Furthermore, here, the suction unit 12 includes two carbon filters 22. Each carbon filter 22 has a capacity of 80 L. Again, the capacity of the carbon filters 22 is chosen to allow for successful testing without compromising the mobility of the mobile device 22. The carbon filters 22 have sufficient volume to allow for testing while mounted on the trailer 18.

[0047] The suction unit 12 further includes a vacuum sensor 28 and a flow sensor 30. The vacuum sensor 28 and the flow sensor 30 are located at the outlet of the demister 20. The vacuum sensor 28 measures the gross vacuum generated by the turbine 26. The flow sensor 30 measures the gross flow rate of the turbine 26. The sensors 28 and 30 thus allow for continuous, reliable, and automatic monitoring of the turbine 26's operation. The gross vacuum and the gross flow rate can be displayed on a control panel 42, as will be described in detail later.

[0048] The injection unit 14 essentially comprises, as illustrated, a compressor 32. The compressor 32 is connected to the injection well PS into which compressed air is injected. As shown in [Fig. 5], the air is injected into the injection well PS from the turbine 36. The air can then pass through the soil, becoming saturated with pollutants, and exit through the extraction well PV1. The extracted air can then follow the same path as described above with reference to [Fig. 4]. It should be noted that in the case of a bubbling test, the turbine 28 does not apply any negative pressure. Conversely, in the case of a combined ventilation / bubbling test, the turbine 28 actively extracts air from the extraction well PV1.

[0049] The injection unit 14 may further include an injection flow sensor 34 and a pressure sensor 36. The pressure sensor 34 measures the gross pressure achieved by the compressor 32. The flow sensor 36 measures the gross flow rate of the compressor 32. The sensors 34 and 36 thus enable continuous, reliable, and automatic monitoring of the compressor operation. The gross pressure and gross flow rate can be displayed on the control panel 42, as will be described in more detail later.

[0050] It is noted that the mobile device 10 comprises a plurality of pipes 38 allowing the circulation of air from the extraction and injection wells PV1, PS to the mobile unit 10 and within the mobile unit 10. The mobile device 10 can further include a plurality of diaphragm valves 40 intended to control the circulation of air within the suction and injection units 12,14.

[0051] The control unit 16 is configured to receive and record data from a plurality of sensors. The data makes it possible to obtain precise information about the site in order to make relevant decisions regarding the pollution control technique to be used and its sizing.

[0052] The plurality of sensors includes the vacuum and flow sensors 28, 30 of the suction unit 12 and the pressure and flow sensors 34, 36 of the injection unit 14. The control unit 16 can automatically regulate the operation of the mobile device 10 during a test. In particular, it is possible to control the gross pressure, the gross vacuum, and the flow rates in the extraction and injection units 12, 14.

[0053] The plurality of sensors further includes remote sensors provided in the PS injection well and the PV1 extraction well. The remote sensors allow for the automatic and continuous acquisition of data on the effect of the test in the PV1 and PS injection and extraction wells. For example, data on the flow rate and the negative / positive pressure in the PV1 extraction well and / or the PS injection well could help to identify the optimal flow rate to be used, beyond which an increase in flow rate does not result in a significant increase in negative or positive pressure in the PV1 and PS wells.

[0054] The plurality of sensors further includes remote sensors provided in control structures PV2, PV3, PZA, PZD, D. The control structures may be extraction wells PV2, PV3 located in the vicinity of the extraction well PV1 and the injection well PS but not connected to the suction unit 12. The control structures may also be a horizontal extraction drain D or a piezometry well PZA, PZD. It is possible to measure the interaction between the extraction or injection well PV1, PS and the control structures PV2, PV3, PZA, PZD, D during a test. These interactions help determine the radius of influence of the injection and / or suction and thus allow for proper sizing of the remediation technique to be used for large-scale treatment.

[0055] Remote sensors include pressure sensors and vacuum sensors. Remote sensors may also include an oxygen sensor, a carbon dioxide sensor, a photoionization detector (PID), and a temperature sensor. It is then possible to obtain pressure and vacuum readings, temperatures, and gas concentrations (oxygen, dioxygen, volatile compounds) during the test. The pressure / vacuum and temperature readings make it possible to identify whether the control structure PV2, PV3, PZA, PZD, D is influenced by the test. The evolution of gas concentrations, for example, makes it possible to visualize the gas circulation within the ground during the test.

[0056] The control unit 16 includes a control panel 42. An example of a control panel 42 is shown in [Fig.6].

[0057] The control panel 42 is adapted to allow a user to select the parameters of a test. These parameters may include, in particular, the choice of the pollution control technique to be tested during the test (ventilation, bubbling, or a combination of both), the duration of the test, the operating speed of the turbine 26 and / or the compressor 32, and the type of test (use of a continuous flow, a continuously increasing flow, or a stepped increase in flow). The user can then configure a test according to the data they wish to collect. The control unit 16 can then perform the test automatically, without subsequent user intervention.

[0058] The control panel 42 is further adapted to display sensor data. The control panel 42 can display the flow rates, pressure, and gross vacuum in the suction and injection units 12, 14. The user can then monitor the proper operation of the mobile device 10 during the test. The control panel 42 can also display the vacuum (PCI to PC6 in [Fig. 6]) and pressure (illustrated PsCl to PsC6 in [Fig. 6]) measured by the remote sensors in the injection well PS, extraction well PV1, and the control structures PV2, PV3, PZA, PZD, D. The user can thus visualize the effect of the injection or extraction in real time. The test can be continuously monitored by the user.

[0059] The control panel 42 can also display additional information, for example, a remaining test time, a temperature or any other information measured by the sensors.

[0060] The control unit 42 further includes a communication module 44. The communication module 44 is, in particular, a wireless communication device, utilizing, for example, the cellular network (GSM, 3G, 4G(-LTE), LTE-M, G). The communication module 44 can enable the transmission of data to a remote server. A user can view the data remotely, for example, via an interface. The data can be processed by a management center immediately upon acquisition.

[0061] Figure 7 illustrates an example of a site suitable for use with the mobile device 10 described above. The site is a site requiring remediation, for which tests can be carried out to validate the suitability of remediation techniques. As illustrated, the site comprises a PS injection well and a plurality of PV1, PV2, and PV3 extraction wells.

[0062] The PS injection well can notably be made using a hollow auger. The PS injection well can, for example, have a diameter between 60 and 90 mm and a depth between 15 and 25 m. The diameter and depth of the well PS injection methods can be chosen according to the characteristics of the soil to be treated.

[0063] The plurality of PV1, PV2, PV3 extraction wells can also be created using a hollow auger. PV1, PV2, PV3 extraction wells can have a diameter between 60 and 90 mm and a depth between 10 and 20 m. The diameter and depth of PV1, PV2, PV3 extraction wells can be chosen according to the characteristics of the soil to be treated. PV1, PV2, PV3 extraction wells can be spaced between 3 and 15 m apart. Extraction wells not used during a test can be used as control wells.

[0064] The site can also be equipped with a horizontal extraction drain D. The drain D can, for example, have a diameter between 740 and 90 mm, a length of approximately 50 mm, and be installed at a depth of approximately 4 m. The horizontal extraction drain D also contributes to the extraction of pollutants from the soil. Here, the extraction drain D can serve as a monitoring structure.

[0065] The site may also include one or more piezometric wells PZA, PZB. The piezometers can serve as PZA, PZB control structures for interactions at the water table, such as dissolved oxygen and water level, during a bubbling test.

[0066] Figure 8 illustrates an example of a graph that can be obtained following a ventilation test. The control unit 16 was ordered to perform a 90-minute test. The extraction flow rate was configured to obtain an initial pressure drop of 10 mbar in the extraction well PV1, and then to increase in steps during the test up to 160 mbar. The pressure drops in three control structures PV2, PV3, and D were plotted as a function of the pressure drop in the extraction well PV1 and time. This graph makes it possible to identify a pressure drop influence extending to the control structure PV3, which is furthest from the extraction well PV1. A circle with a diameter corresponding to the distance separating this control structure PV3 from the extraction well PV1 can be considered the radius of influence. The influence becomes more pronounced from the third step onward.The flow rate in the PV1 extraction well associated with this level can be chosen as the optimal flow rate.

[0067] It should be noted that other relevant information could be derived from the data recorded by the control unit 16 to qualify the test. The flow rate and the pressure drop in the PV1 extraction well could help to identify the optimal flow rate, beyond which an increase in flow rate does not lead to a significant increase in the pressure drop in the PV1 extraction well. The evolution of gas concentrations (oxygen, dioxygen, volatile compounds) allows visualization of gas circulation during the test.

[0068] Furthermore, several ventilation tests could be implemented to to gather more information. The tests can be stepped, at increasing flow rates or continuous flow rates, and for varying durations. The tests can also be carried out on different PV2 and PV3 extraction wells. All the information obtained can help validate the effectiveness of the ventilation technique and determine the appropriate treatment.

[0069] Figure 9 illustrates an example of a graph that can be obtained following a bubbling test. Control unit 16 was ordered to perform a 50-minute test. The injection flow rate was configured to increase in steps during the test. The pressures in five control structures PZA, PV1, PV2, PV3, and PVD were plotted as a function of time and the injection flow rate. It can be seen that no influence is obtained between the injection well PS and the control structure PZD furthest from the injection well PS. Thus, the radius of influence can be defined as a circle with a perimeter equal to the distance between the fourth furthest control structure, PV3, and the injection well PS.

[0070] Here again, other relevant information could be derived from the data recorded by the control unit 16 to measure the effect of bubbling. The flow rate and pressure in the injection well could help to identify the optimal flow rate, beyond which an increase in flow rate does not lead to a significant increase in the pressure drop in the injection well. The evolution of gas concentrations (oxygen, dioxygen, volatile compounds) allows visualization of gas circulation during the test.

[0071] Furthermore, several bubbling tests could be carried out to collect more information. The tests could be stepped tests, tests at increasing flow rates or at a continuous flow rate, and for varying durations. All the information obtained can help validate the effectiveness of the bubbling technique and determine the appropriate treatment.

[0072] In addition, the control unit 16 could also be ordered to perform a combined ventilation and bubbling test. This makes it possible to obtain information to validate the effectiveness of the combined technique and to determine the appropriate treatment.

Claims

Demands

1. Mobile soil remediation device (10) for conducting tests on a site to be remediated, the device (10) comprising: • an air extraction unit (12) adapted to extract air from an extraction well (PV1); • an air injection unit (14) adapted to inject air into an injection well (PS); and; • a control unit (16) configured to control an air suction flow rate in the extraction well (PV1) and / or an air injection flow rate in the injection well (PS) and to record data measured by at least one sensor provided in the extraction well (PV1), in the injection well (PS) and / or in at least one control structure (PV2, PV3, D, PZA, PZB), the control structure (PV2, PV3, D, PZA, PZB) being remote from the extraction well (PV1) or the injection well (PS).

2. Mobile device (10) according to claim 1, wherein the measured data are at least one of: an injected air flow rate, an extracted air flow rate, a temperature, a pressure, a vacuum and a gas concentration.

3. Mobile device (10) according to claim 1 or 2, wherein the mobile unit (10) further comprises a trailer (18) on which is mounted the suction unit (12), the injection unit (14) and the control unit (16).

4. Mobile device (10) according to any one of the preceding claims, wherein the suction unit (12) comprises a turbine (26) with a variable suction capacity up to about 85 m3 / h and a maximum relative depression of about -210 mbar.

5. Mobile device (10) according to any one of the preceding claims, wherein the suction unit (12) comprises at least one carbon filter (22) with a capacity of about 80 L.

6. Mobile device (10) according to any one of the preceding claims, wherein the injection unit (14) comprises a compressor (32) with a modulating blowing capacity up to about 40m3 / h and a maximum relative pressure of 800 mbar.

7. Mobile device (10) according to any one of the preceding claims, wherein the control unit (16) comprises a control panel (42) configured for viewing and recording data, selecting the suction flow rate and / or injection flow rate and a test duration.

8. Mobile device (10) according to any one of the preceding claims, wherein the control unit (16) includes a communication device (44) configured to communicate data to a remote interface.

9. A method for carrying out tests of remediation techniques comprising: - Selecting an air injection rate in an extraction well (PV1) and / or an air extraction rate in an injection well (PS) and a test duration; - Extracting air from the extraction well (PV1) and / or injecting air into the injection well (PS) according to the selected rate and for the duration of the test; - Recording data measured by at least one sensor provided in the extraction well (PV1), in the injection well (PS) and / or in a control structure (PV2, PV3, D, PZA, PZB), the control structure PV2, PV3, D, PZA, PZB) being distant from the extraction well (PV1) or the injection well (PS).

10. A method according to claim 9, wherein the air injection rate and / or the extraction rate increases in steps during the duration of the test.

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