System for comprehensive treatment of saturated zone and aerated zone

Abstract

The present invention provides a system for comprehensive treatment of saturated zone and aeration zone, including an injection system, a multiphase extraction system and a tail gas and tail water treatment system. The injection system injects high-pressure air into the soil through air compression equipment and injection wells; the multiphase extraction system consists of a gas phase extraction well, a multiphase extraction well, and a NAPL phase extraction device. The gas phase extraction well is used to extract polluted gas in the soil, and the groundwater extraction pipe in the multiphase extraction well can extract polluted water. The NAPL phase extraction device can accurately extract NAPL phase pollutants; the tail gas and tail water treatment system can process the extracted gas phase, liquid phase and NAPL phase until they are safely discharged or collected. The present invention reduces the repair time and solves the tailing problem by introducing multiphase extraction technology and NAPL precise extraction technology.

Description

Technical Field

[0001] The invention relates to a system for extracting and treating soil gas, groundwater and floating oil layer in underground contaminated areas. Background Art

[0002] For underground contaminated areas, multiphase extraction technology is generally used for treatment. That is, through vacuum extraction, soil gas, groundwater and floating oil layers in underground contaminated areas are extracted to the ground for phase separation and treatment, so as to control and repair organic pollutants in the soil and groundwater and achieve the purpose of site remediation.

[0003] Multiphase extraction has the advantages of small environmental disturbance and simultaneous restoration of groundwater and soil, and is suitable for polluted sites such as oil companies and gas stations.

[0004] However, since the LNAPL phase (light non-aqueous phase liquid) floats on the groundwater, it is difficult to accurately extract the LNAPL phase using traditional multiple extraction technologies, which often causes tailing (i.e., the LNAPL phase accumulates again after a period of time after the treatment is completed). Summary of the invention

[0005] The object of the present invention is to provide a system for comprehensive treatment of saturated zone and aeration zone, which can improve the treatment speed on the one hand and eliminate the tailing phenomenon on the other hand.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A system for comprehensive treatment of saturated zone and aeration zone, characterized by comprising an injection system, a multiphase extraction system and a tail gas and tail water treatment system, wherein:

[0008] The injection system comprises an air compression device and an injection well, the air compression device provides high-pressure air to the air injection pipe, the air injection pipe extends into the injection well at a depth below the groundwater level, and the opening depth of the injection well is 10-100 cm above the highest groundwater level throughout the year;

[0009] The multiphase extraction system is composed of a gas phase extraction well, a gas phase extraction pipeline, an extraction fan, a multiphase extraction well, a groundwater extraction pipe, an extraction water pump and a NAPL phase extraction device, wherein:

[0010] The screening depth of the gas phase extraction well is above the groundwater level, the gas phase extraction pipeline provided therein is connected to the extraction fan, and the downstream of the extraction fan is connected to the bioreactor;

[0011] The opening depth of the multiphase extraction well is 10-100 cm above the groundwater level, wherein the groundwater extraction pipe is located at the target depth of groundwater level restoration and is connected to the extraction water pump, and the downstream of the extraction water pump is connected to the bioreactor;

[0012] The NAPL phase extraction device comprises a NAPL extraction pipe and a NAPL extraction pump, wherein the lower end of the NAPL extraction pipe is located at the depth of the NAPL phase, the upper end of the NAPL extraction pipe is connected to the NAPL extraction pump, the downstream of the NAPL extraction pump is connected to a sedimentation tank, the sedimentation tank has a water phase outlet and a NAPL phase outlet, and the water phase outlet is connected to the bioreactor;

[0013] The tail gas and tail water treatment system comprises the sedimentation tank and the bioreactor.

[0014] The system for comprehensive treatment of saturated zones and aerated zones, wherein: the air compression equipment is connected to a plurality of gas injection pipelines via a gas distributor, and the terminal of each gas injection pipeline is connected to an injection well via one of the gas injection pipes.

[0015] The system for comprehensive treatment of saturated zones and aerated zones, wherein: the gas distributor is provided with a vortex flowmeter, a pressure gauge and an electric valve, which can evenly distribute the compressed air generated by the air compression equipment to each injection well, and can also monitor the flow and pressure in each gas injection pipeline.

[0016] The system for comprehensive treatment of saturated zone and aeration zone, wherein: a gas-liquid separator is provided on the gas phase extraction pipeline, the separated polluted gas is extracted by the extraction fan and enters the bioreactor for treatment, and the separated polluted liquid is sent to the bioreactor for treatment via a drainage pump.

[0017] The system for comprehensive treatment of saturated zone and aeration zone, wherein: the tail gas and tail water treatment system also includes a NAPL recovery tank, and the NAPL phase outlet of the sedimentation tank is connected to the NAPL recovery tank.

[0018] The system for comprehensive treatment of saturated zones and aerated zones, wherein: the gas phase extraction pipeline is also provided in the multiphase extraction well, and the gas phase extraction pipeline in the multiphase extraction well is also connected to the extraction fan.

[0019] The system for comprehensive treatment of saturated zone and aeration zone, wherein: the NAPL phase extraction device includes a positioner, an online density meter, the NAPL extraction pipe and the NAPL extraction pump, the online density meter can detect the depth position of the NAPL phase, which is fixed to the groundwater extraction pipe through the positioner, the groundwater extraction pipe is a hose and is connected to a winch, the depth position of the positioner can be controlled by the winch, and the lower end of the NAPL extraction pipe is fixed to the positioner.

[0020] The present invention reduces the repair time and solves the tailing problem by introducing AS technology and NAPL precise extraction technology. At the same time, the bioreactor is used as the tail gas and tail water treatment equipment, which will not produce secondary pollution and improve the overall environmental friendliness of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall structure of the system for comprehensive treatment of saturated zone and aeration zone provided by the present invention.

[0022] Figure 2 It is a schematic diagram of the enlarged structure of the locator of the NAPL phase extraction device.

[0023] Explanation of the reference numerals: air compression equipment 1; injection well 2; gas distributor 3; gas injection pipeline 4; gas injection pipe 5; gas phase extraction well 6; gas phase extraction pipeline 7; extraction fan 8; multiphase extraction well 9; groundwater extraction pipe 10; extraction water pump 11; NAPL phase extraction device 12; gas-liquid separator 13; bioreactor 14; drainage pump 15; positioner 16; online density meter 17; NAPL extraction pipe 18; NAPL extraction pump 19; sedimentation tank 20; NAPL recovery tank 21. DETAILED DESCRIPTION

[0024] like Figure 1 As shown, the present invention provides a system for comprehensive treatment of saturated zone and aeration zone, including an injection system, a multiphase extraction system and a tail gas and tail water treatment system, wherein:

[0025] The injection system comprises an air compression device 1 and an injection well 2. The air compression device 1 is connected to several injection pipes 4 through a gas distributor 3. The terminal of each injection pipe 4 is connected to an injection pipe 5. The injection pipe 5 extends into the injection well 2 at a depth below the groundwater level. The opening depth of the injection well 2 is 10-100 cm above the highest groundwater level throughout the year, so as to achieve the restoration effect of the air zone at different water levels throughout the year. The air compression provides high-pressure air to the injection pipe 5, and accelerates the transfer of VOCs pollutants from soil particles or groundwater to soil gas through air injection. The gas distributor 3 is provided with a vortex flowmeter, a pressure gauge and an electric valve, which can evenly distribute the compressed air generated by the air compression device 1 to each injection well 2, and can also monitor the flow and pressure in each injection pipe 4.

[0026] The multiphase extraction system is composed of a gas phase extraction well 6, a gas phase extraction pipeline 7, an extraction fan 8, a multiphase extraction well 9, a groundwater extraction pipe 10, an extraction water pump 11 and a NAPL phase extraction device 12, wherein:

[0027] The screening depth of the gas phase extraction well 6 is located above the groundwater level, and the gas phase extraction pipeline 7 provided therein is connected with the extraction fan 8 to extract the soil gas polluted by VOCs contained in the soil. A gas-liquid separator 13 is provided on the gas phase extraction pipeline 7, and the separated polluted gas is extracted and enters the bioreactor 14 for treatment, and the separated polluted liquid is sent to the bioreactor 14 for treatment through the drainage pump 15; the bioreactor 14 can treat tail gas and tail water at the same time, which saves costs and also saves equipment floor space;

[0028] The opening depth of the multiphase extraction well 9 is located 10-100 cm above the groundwater level, so as to achieve accurate extraction of LNAPL at different water levels throughout the year. The groundwater extraction pipe 10 is located at the target depth of groundwater level remediation and is connected to the extraction water pump 11. The extracted water is treated by the bioreactor 14 and then discharged in compliance with the standards.

[0029] The multiphase extraction well 9 is also provided with the gas phase extraction pipeline 7, which can collect the VOCs pollutants volatilized from the groundwater in the multiphase extraction well 9 to prevent the polluted gas from entering the soil through the sieve holes; the gas phase extraction well 6 and the multiphase extraction well 9 share an extraction fan 8, which can greatly save project costs;

[0030] The multiphase extraction well 9 is also provided with a NAPL phase extraction device 12 for accurately extracting NAPL phase pollutants. The NAPL phase extraction device 12 is composed of a positioner 16, an online density meter 17, a NAPL extraction pipe 18 and a NAPL extraction pump 19. The online density meter 17 is located on the positioner 16. The positioner 16 is annular and is sleeved on the lower end of the groundwater extraction pipe 10. The groundwater extraction pipe 10 is a hose and is connected to a winch. The winch combined with the online density meter 17 can control the positioner 16 to be located at the depth position where the NAPL phase is located. The NAPL extraction pipe 18 is also fixed on the positioner 16, and the lower end of the NAPL extraction pipe 18 is exposed from the positioner 1 6, the upper end is connected to the NAPL extraction pump 19, the downstream of the NAPL extraction pump 19 is connected to the sedimentation tank 20, the sedimentation tank 20 has a water phase outlet and a NAPL phase outlet, the water phase outlet is connected to the bioreactor 14, and the NAPL phase outlet is connected to the NAPL recovery tank 21; when in use, the ground control system can control the start and stop of the winch according to the data fed back by the density meter, so as to control the positioner 16 to stop accurately at the NAPL layer. When the positioner 16 is located at the NAPL layer, the NAPL extraction pump 19 starts to work, and the extracted liquid first enters the sedimentation tank 20 to separate the water phase and the NAPL phase, the NAPL phase enters the NAPL recovery tank 21 for collection, and the water phase enters the bioreactor 14 for treatment;

[0031] The tail gas and tail water treatment system includes the sedimentation tank 20, the NAPL recovery tank 21 and the bioreactor 14; the sedimentation tank 20 is mainly used to separate the liquid phase extracted by the NAPL phase extraction device 12 from the NAPL phase, the NAPL phase recovery tank is used to store and recover the separated NAPL phase, and the bioreactor 14 is used to treat the extracted polluted water and polluted gas.

[0032] It can be seen from the above that the advantages of the present invention are:

[0033] (1) This system can simultaneously repair soil and groundwater.

[0034] (2) This system is designed for precise extraction of the tailing phenomenon of groundwater remediation caused by NAPL, effectively solving the problem of tailing of groundwater remediation caused by NAPL, and at the same time completing the resource utilization of NAPL phase.

[0035] (3) A gas distributor 3 is provided on the injection pipeline, which can evenly distribute the compressed air generated by the air compression device to each injection well 2 and monitor the flow of the press in each injection well 2 at the same time.

[0036] (4) This system uses a bioreactor 14 to treat tail water and tail gas. Compared with activated carbon adsorption treatment, there is no need to treat the waste activated carbon, which reduces the system operation cost.

[0037] The above description is only illustrative rather than restrictive of the present invention. Those skilled in the art will understand that many modifications, changes or equivalents may be made without departing from the spirit and scope defined by the claims, but all will fall within the scope of protection of the present invention.

Claims

1. A system for comprehensive treatment of saturated zone and aeration zone, characterized by: It includes injection system, multiphase extraction system and tail gas and tail water treatment system, including: The injection system comprises an air compression device and an injection well, the air compression device provides high-pressure air to the air injection pipe, the air injection pipe extends into the injection well at a depth below the groundwater level, and the opening depth of the injection well is 10-100 cm above the highest groundwater level throughout the year; The multiphase extraction system includes a gas phase extraction well, a gas phase extraction pipeline, an extraction fan, a multiphase extraction well, a groundwater extraction pipe, an extraction water pump and a NAPL phase extraction device, wherein: The screening depth of the gas phase extraction well is above the groundwater level, the gas phase extraction pipeline provided therein is connected to the extraction fan, and the downstream of the extraction fan is connected to the bioreactor; The opening depth of the multiphase extraction well is 10-100 cm above the groundwater level, wherein the groundwater extraction pipe is located at the target depth of groundwater level restoration and is connected to the extraction water pump, and the downstream of the extraction water pump is connected to the bioreactor; The NAPL phase extraction device comprises a NAPL extraction pipe and a NAPL extraction pump, wherein the lower end of the NAPL extraction pipe is located at the depth of the NAPL phase, the upper end of the NAPL extraction pipe is connected to the NAPL extraction pump, the downstream of the NAPL extraction pump is connected to a sedimentation tank, the sedimentation tank has a water phase outlet and a NAPL phase outlet, and the water phase outlet is connected to the bioreactor; The tail gas and tail water treatment system comprises the sedimentation tank and the bioreactor; Wherein, a gas-liquid separator is provided on the gas phase extraction pipeline, and the separated polluted gas is extracted by the extraction fan and enters the bioreactor for treatment, and the separated polluted liquid is sent to the bioreactor for treatment through the drainage pump; Wherein, the multiphase extraction well is also provided with the gas phase extraction pipeline, and the gas phase extraction pipeline in the multiphase extraction well is also connected to the extraction fan; The NAPL phase extraction device includes a positioner, an online density meter, the NAPL extraction pipe and the NAPL extraction pump. The online density meter can detect the depth position of the NAPL phase and is fixed to the groundwater extraction pipe through the positioner. The groundwater extraction pipe is a hose and is connected to a winch. The depth position of the positioner can be controlled by the winch. The lower end of the NAPL extraction pipe is fixed to the positioner.

2. The system for comprehensive treatment of saturated zone and aeration zone according to claim 1, characterized in that: The air compression equipment is connected to a plurality of gas injection pipelines through a gas distributor, and the terminal of each gas injection pipeline is connected to an injection well through one of the gas injection pipes.

3. The system for comprehensive treatment of saturated zone and aeration zone according to claim 2, characterized in that: The gas distributor is provided with a vortex flowmeter, a pressure gauge and an electric valve, which can evenly distribute the compressed air generated by the air compression equipment to each injection well and can also monitor the flow and pressure in each gas injection pipeline.

4. The system for comprehensive treatment of saturated zone and aeration zone according to claim 1, characterized in that: The tail gas and tail water treatment system further comprises a NAPL recovery tank, and the NAPL phase outlet of the sedimentation tank is connected to the NAPL recovery tank.

Images