KR100495773B1 - Device for recovery of polluted soil and lnapl with floating and skimming pipe system - Google Patents

Abstract

The present invention relates to an apparatus for purifying contaminated soil and groundwater, and the apparatus of the present invention is a device used in a conventional method for extracting soil vapor, which floats on the groundwater surface while floating on the groundwater surface in response to changes in the groundwater level. A floating skimming burette collecting specific gravity-insoluble organic solvent (LNAPL), a first pipe attached to the burette to extract LNAPL, and a communication structure having a length-controlled communication structure with the first pipe. There is characterized in that it comprises a floating skimming pipe system consisting of a second pipe to extract the soil gas through this.

Description

DEVICE FOR RECOVERY OF POLLUTED SOIL AND LNAPL WITH FLOATING AND SKIMMING PIPE SYSTEM}

The present invention relates to an apparatus for purifying contaminated soil and groundwater, and the apparatus of the present invention is a low specific gravity-non-insoluble organic solvent (Light non-) while floating on the groundwater surface in response to the change of groundwater in a conventional soil vapor extraction apparatus. A floating & skimming pipe system consisting of a floating briquette for extracting an aqueous phase liquid layer (hereinafter referred to as 'LNAPL') and a second pipe with a screen and a first pipe attached to the briquette It is characterized by.

The conventional soil vapor extraction method for the purification of contaminated soil was a method of treating by vacuuming the soil to volatilize the contaminants in the soil. This technique has an excellent effect on the treatment of volatile contaminants in the soil, but is less effective when the groundwater level fluctuates severely or the water level is high. In addition, in order to simultaneously treat the contaminated groundwater, two pumps for soil contaminant extraction and contaminated groundwater extraction must be installed and used, resulting in difficulty in operation.

Recently, multi-phase extraction for simultaneous purification of contaminated groundwater and soil has been studied. It is divided into two ways as follows. Each of these techniques has its problems.

In the first method, as shown in FIG. 1, two extraction pipes 12 and 14 are separately installed in the extraction well system 15 to pump the groundwater 11 and the soil gas 13 to the pump 16 and the vacuum blower. It is a method of extracting from each extraction tube using (17). However, this method uses two pump systems 16 and 17, which increases the cost. In addition, it is a technology that extracts the contaminated groundwater 11 itself rather than selective LNAPL extraction. Because of the large amount of groundwater extraction, the oil separator (not shown) and the treatment tank (not shown) become large, which is expensive and uneconomical. .

The second method is a technique of simultaneously extracting the groundwater 24 and the soil gas 23 through one extraction tube 21 as shown in FIG. This is a technique using a single pump system in the same pipe (21). However, since a technique for selectively extracting LNAPL has not yet been developed, it must be artificially controlled by manpower for selective extraction. As a result, groundwater level fluctuations cannot be adequately reacted, so additional costs are caused for the occurrence of additional soil contamination caused by groundwater level fluctuations and the resulting soil remediation. In addition, this method is also expensive and uneconomical, since a high vacuum pump is used.

The present invention is to solve the problems of the existing steam extraction method for the purification of contaminated soil and ground water as described above, by selectively extracting only the soil gas and LNAPL layer while flowing in accordance with the change of groundwater level, It minimizes water treatment costs, minimizes additional soil contamination, and simultaneously removes soil gas and LNAPL layers by using a single extraction system with a single pump system to reduce the maintenance and treatment costs. It aims to provide.

The present invention relates to an apparatus for purifying contaminated soil and groundwater, characterized in that it comprises a floating skimming pipe system composed of a floating pipe and a double pipe in an existing soil vapor extraction apparatus. The floating skimming pipe system here

A floating skimming beret (1) having a concave shape inside, capable of collecting the LNAPL layer while floating on the water surface;

One end is attached to the recessed portion inside the floating bridle, and there is an extracting means at the attachment portion to collect the LNAPL layer flowing into the bridle, and a screen for collecting the LNAPL layer near the extraction means ( 51) formed, the other end having a first pipe 3 in communication with the second pipe 4 so that the length from the floating skimming bleed to the ground can be changed fluidly; And

One end is in communication with the first pipe (3), the other end is through the outside to send the collected soil vapor and LNAPL to the extraction pump and gas / liquid separator, and on the pipe a screen for soil gas collection (5). ) With a second pipe 4.

Hereinafter, the floating skimming pipe system of the soil and groundwater purification apparatus according to the present invention will be described in detail with reference to the accompanying FIG.

Floating skimming beret (1) is a function of collecting the LNAPL layer while floating on the water surface. Since the floating skimming beret should be located above the groundwater level, it is preferable to manufacture using a synthetic resin, for example, a polyethylene-based resin in consideration of specific gravity. Floating skimming bridles have a weir 2 at the top for efficient collection of the LNAPL layer. The result of the present invention can be obtained when using a floating skimming beret of specific gravity such that the lower end of the weir is located at the interface between the LNAPL layer and the groundwater (FIG. 5).

The floating skimming beret has a concave shape downwards towards the center to effectively accommodate the flow of LNAPL layers. 5 illustrates an exemplary shape for the shape of the floating skimming beret, but is not limited thereto.

One end of the first pipe 3 is attached to the concave portion of the floating skimming beret. Since there is no great limitation in the manner of attaching the first pipe to the floating skimming bridle (1), it can be combined using a bond or a helical screw. The portion where the first pipe 3 is attached to the floating skimming beret 1 is collected inside the first pipe so that the LNAPL received inside the floating skimming beret is extracted to the ground through the first pipe 3. There is a facility for For example, a hole may be made in the attachment portion described above. At this time, the shape, size, number of holes is not limited.

The screen 51 is provided in the vicinity of the place where the first pipe is attached to the floating skimming bridle. This is an effective means of collecting LNAPLs, especially when collecting LNAPLs above the bures. In this case, the screen is a general term known in the art, and is formed along the outer circumference of the pipe, and is not limited in length, and may be any shape such as a hole or a long groove. The width of the screen is less than 2mm. In general, 1mm is suitable, 0.5mm or less is most suitable. If the screen width exceeds 2mm, it is not suitable because soil particles may enter.

The other end of the first pipe 3 is in communication with the second pipe 4. The communication structure is in communication with the first pipe and the second pipe so as to maintain the communication structure of the first pipe and the second pipe even when the distance from the floating skimming brim connected to one end of the first pipe to the ground varies. For example, a fastening structure in which the first pipe is inserted into the second pipe is possible.

One end of the second pipe 4 is connected to and communicated with the first pipe in the same manner as above, and the other end is externally directed to send the collected soil vapor and LNAPL to the extraction pump and the gas / liquid separator. . The second pipe is provided with a screen 5 for collecting soil gas.

The material of the first pipe and the second pipe is not particularly limited. Stainless, PVC, or acrylic pipes are suitable as examples.

LNAPL and gas extracted by this floating skimming pipe system are treated by the general method of soil vapor extraction. An overview of this process is shown in FIG. 4.

The size and capacity of the extraction well 6 may vary depending on the situation of the site. In the present invention, while the above-mentioned floating skimming pipe system is maintained in connection with the ground treatment facility shown in FIG. In addition, since the LNAPL should be extracted by generating an appropriate vacuum, the connection of the first pipe 3 and the second pipe 4 should be made so as not to interfere with the movement of the floating skimming beret. The floating skimming beret is selectively collected only through the weir 2 and the screen 51 while moving up and down according to the change of the groundwater level.

According to the apparatus of the present invention, the LNAPL and the soil gas can be extracted simultaneously using a single pump. Simultaneous extraction of the LNAPL and gas using the purification device including the floating skimming pipe system of the present invention will be described with reference to FIGS. 3 and 4. First, a vacuum is applied to the extraction well 6 using the extraction pump 41. When the soil gas is introduced into the screen 7, it is extracted through the screen 5 of the second pipe 4. In addition, the LNAPL introduced into the extraction well 6 while being vacuumed on the second pipe 4 is introduced into the barrel through the weir 2 of the floating skimming bowl 1 (FIG. 5) or through the screen 51. It flows into one pipe (FIG. 5), moves through the first pipe 3, and is extracted into the second pipe 4. The extracted LNAPL and soil gas are separated through a gas / liquid separator, which is then processed and disposed of by the gas and liquid treatment devices, respectively.

Hereinafter, the present invention will be described in more detail with reference to the following examples. The following examples are merely examples for illustrating the present invention and do not limit the protection scope of the present invention.

Example

In this embodiment, the groundwater and contaminated soil purification apparatus including the floating skimming pipe system was experimented using a water tank containing water before directly performing the soil. Extraction wells were installed in a tank containing water and diesel and extracted with a 3-horsepower vacuum blower.

The diameter of the extraction well was 100mm and the length of 2m was used. A screen of width 1mm was made at a distance of 20mm at 1m below the pipe. In addition, inside the extraction well, the first pipe used a 2-inch diameter pipe and the second pipe used a 1 / 4-inch diameter pipe, and the floating skimming burero was provided with a weir-shaped conical burette at the bottom. The second pipe was bonded to the floating skimming bridle and made six holes 1/8 inch in diameter near the attachment surface.

Since it was carried out in a pilot experiment in the laboratory, the experiment was carried out by installing an air injection valve and adjusting the suction power and air flow rate of the blower.

In this example, we tried to determine the possibility of simultaneous extraction of LNAPL and soil gas, and the extraction capacity according to the suction power and soil characteristics of the blower. Figure 6 looks at the flow rate of the extracted soil gas layer and LNAPL layer according to adjusting the suction force (vacuum pressure) of the blower. As shown in FIG. 6, the flow rate of the extracted soil gas increases as the suction force (vacuum pressure) of the blower increases. In addition, as shown in FIG. 7, as the suction force (vacuum pressure) of the blower increases, the amount of LNAPL extracted increases. This indicates that the removal of contaminants is effective with increasing blower capacity. However, because the soil permeability is constant, it does not increase indefinitely, but the rate of increase decreases in a certain range.

Figure 8 looked at the amount of soil gas and LNAPL extracted according to the soil permeability while varying the air injection rate in the extraction well. The suction power of the blower was carried out while maintaining a constant. 8 shows that the amount of soil gas extracted decreases as the vacuum pressure of the extraction well increases. 9 shows that the amount of LNAPL extracted is smaller as the vacuum pressure of the extraction well increases. This shows that soils with low air permeability are disadvantageous for the removal of contaminants. On the other hand, coarse soils with good air permeability show effective removal of contaminants.

When using the device of the present invention can extract LNAPL of contaminated soil and groundwater at the same time, it can be effectively applied to the purification of soil, groundwater contaminated with volatile organic contaminants and LNAPL. In addition, it can be effectively applied in maintenance and economical efficiency compared to the prior art such as the multiple vapor extraction method that has been studied a lot recently.

1 is a diagram illustrating a conventional double-hole extraction pump (Downhole-pump Extraction Well).

FIG. 2 is a diagram illustrating a conventional Drop-Tube Entrainment Extraction Well. FIG.

3 is a diagram illustrating the structure of a floating & skimming extraction well in the present invention.

FIG. 4 is a schematic cross-sectional view of a soil and groundwater purification apparatus including a Floating & Skimming Extraction Well system. FIG.

5 is an enlarged cross-sectional view of the floating skimming bridle.

6 and 7 are graphs showing the removal amount of soil gas and LNAPL according to the blower capacity.

8, 9 is a graph showing the removal amount of soil gas and LNAPL according to the soil permeability.

<Explanation of symbols for the main parts of the drawings>

1.Floating skimming beret

2 ... weir

3.first pipe

4 ... the second pipe

5. Screen of the second pipe

6. Extraction well

7. Screen of Extraction Control

Claims (4)

In the device for purifying contaminated soil and ground water by the soil vapor extraction method, It is made of a material that can float on the surface of the groundwater, and can collect a low specific gravity-insoluble organic solvent (LNAPL) layer while floating on the surface of the groundwater, and the weir (2) is installed on the surface, and the inside is concave. Floating skimming beret (1); One end is attached to the recessed portion of the floating skimming brim, and an extraction means and a screen are provided at the attachment to collect the low specific gravity-insoluble organic solvent (LNAPL) layer inside or on the bridle. The other end has a structure in which the length from the floating skimming bleed to the ground is changed into the inside of the second pipe 4 so as to be fluidly changed, and the first pipe communicating with the second pipe 4 ( 3); And One end is in communication with the first pipe (3), the other end is through the outside to send the collected soil vapor and low specific gravity-insoluble organic solvent to the extraction pump and the gas / liquid separator, and the soil on the pipe Apparatus for purifying contaminated soil and ground water, characterized in that it comprises a floating skimming pipe system consisting of a second pipe (4) with a screen for gas collection. delete delete 2. The apparatus for purifying contaminated soil and ground water according to claim 1, wherein a plurality of holes are drilled as extraction means of the attachment portion of the first pipe (3) attached to the floating skimming brim (1).