KR102739990B1 - Heavy meatal's contaminated soil remediation system in vadose zone using movable injection well and remediation method having the same - Google Patents

Abstract

Embodiments of the present invention effectively remove heavy metal pollutants distributed in an unsaturated zone by quickly moving and installing a mobile injection well to railway-contaminated soil requiring purification, and also provide convenience to workers by making it easier to install and detach the mobile injection well from the railway-contaminated soil. The system for purifying heavy metal pollutants in an unsaturated zone using a mobile injection well according to an embodiment of the present invention comprises: a mobile injection well equipped with a tapered surface with a sharp tip so that it can be driven into railway-contaminated soil; an injection facility connected to a manifold block and a supply line that protrudes when the mobile injection well is driven into the ground to provide an organic acid dissolving agent to the mobile injection well; an extraction well that extends to below the groundwater surface so that the organic acid dissolving agent provided from the mobile injection well can flow into the groundwater through the heavy metal-contaminated zone in the unsaturated zone above the groundwater surface; a water treatment device for pumping out and treating groundwater containing a complex compound formed by the organic acid dissolving agent reacting with a heavy metal from the extraction well; and a water treatment device for treating groundwater by pumping out groundwater containing a complex compound formed by the reaction of the heavy metal with the organic acid dissolving agent at the top of the mobile injection well. It is characterized by including a vibrating impact device that generates a striking force capable of striking the manifold block and embedding the tapered surface into the railway contaminated soil.

Description

{HEAVY MEATAL'S CONTAMINATED SOIL REMEDIATION SYSTEM IN VADOSE ZONE USING MOVABLE INJECTION WELL AND REMEDIATION METHOD HAVING THE SAME}

The present invention relates to a system and method for purifying heavy metal-contaminated soil in an unsaturated zone using a mobile injection well, and more specifically, to a system and method for purifying heavy metal-contaminated soil in an unsaturated zone using a mobile injection well, which effectively removes heavy metal pollutants distributed in an unsaturated zone by quickly moving and installing a mobile injection well to railway-contaminated soil requiring purification, and also provides convenience to workers by making it easier to install and detach the mobile injection well from the railway-contaminated soil.

With the opening of KTX, railways are taking up an important position in domestic transportation distribution, and their importance is increasing day by day. The 100-year history of railways shows the development of the railway sector, but on the other hand, it also means that soil pollution caused by railways has been occurring steadily for 100 years. Soil pollution caused by railways is divided into oil pollution such as diesel fuel, lubricants used in engines and switches, and heavy metal pollution caused by wear and tear of railway tracks. Large-scale railway-contaminated soil remediation projects conducted to date have targeted euro-contaminated soil. Oil-contaminated soil from railways is being remediated by biological and chemical oxidation methods. However, the extent of heavy metal contamination is not even properly identified.

In general, heavy metal contaminated soil is purified by methods such as soil washing, solidification/stabilization, and electrokinetic purification. In advanced countries, the solidification/stabilization method is widely used, but in Korea, there are limitations in the soil contamination process test method for Zn, Ni, etc., which make it difficult to be recognized as purified even if the solidification/stabilization method is applied, and so it remains in the research stage.

The most widely used method for purifying heavy metal contaminated soil in Korea is the soil washing method. This soil washing method involves excavating contaminated soil, separating particles, mixing the soil with a washing solution, and removing heavy metals from the soil by moving them into the washing solution. The soil washing method is widely used because it is relatively simple and efficient.

However, in the case of railway site soil, excavation to remove heavy metal contaminants is difficult, and long-term heavy metal contamination is not easy to remove, so simple soil washing methods have the problem of low efficiency. Therefore, there is an increasing demand for on-site purification technology for heavy metal contaminated soil that can effectively purify heavy metal contaminated soil on railway sites without on-site excavation.

(Document 1) Republic of Korea Patent Publication No. 10-0353301 (Document 2) Republic of Korea Patent Publication No. 10-1579241

Embodiments of the present invention provide a system and method for purifying heavy metal pollutants in an unsaturated zone using a mobile injection well, which effectively removes heavy metal pollutants distributed in an unsaturated zone by quickly moving and installing a mobile injection well to railway-contaminated soil requiring purification, and which enables easier installation and separation of the mobile injection well from the railway-contaminated soil, thereby providing convenience to workers.

The problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

In one embodiment of the present invention, a mobile injection well having a tapered surface with a sharp tip so as to be driven into railway-contaminated soil, an injection facility connected to a manifold block and a supply line that protrudes when the mobile injection well is driven into the ground to provide an organic acid dissolving agent to the mobile injection well, a plurality of extraction wells that are installed to extend below the groundwater level so that the organic acid dissolving agent provided from the mobile injection well can flow into the groundwater through an unsaturated heavy metal contaminated zone above the groundwater level, a water treatment device for pumping up groundwater containing a complex compound formed by a reaction of the organic acid dissolving agent with a heavy metal from the extraction well and treating it, and a vibration impact device that generates a striking force so as to strike the manifold block at the top of the mobile injection well so as to drive the tapered surface into the railway-contaminated soil.

In addition, the mobile injection unit includes an organic acid elution agent manifold for distributing the flow of the organic acid elution agent provided from the supply line to the heavy metal contamination area without using power and evenly discharging it by gravity, and the organic acid elution agent manifold is characterized by including a manifold block through which the organic acid elution agent is delivered through an inlet connected to the supply line, and a plurality of nozzles that are formed to extend radially outwardly of the manifold block and are installed in a plurality of spaced apart manners along the longitudinal direction of the manifold block.

In addition, the vibration striking device is characterized by including a main body having an L shape, a movable member provided on both sides of the lower portion of the main body, a movable injection well striking member provided on the front end of the main body and guided by the main body to strike and strike the upper end of the movable injection well while moving up and down, and a connecting member that allows the movable injection well striking member to be connected to the main body so as to be able to move up and down.

In addition, the injection facility is characterized by including a storage tank storing an organic acid eluent for supplying to the mobile injection well, a plurality of supply lines in the form of flexible pipes for supplying the organic acid eluent stored in the storage tank to a plurality of mobile injection wells, and a distributor connected to the storage tank so that the plurality of supply lines can be connected.

In addition, it is characterized by further including a connecting socket for connecting the mobile injection device and the supply line to each other.

In addition, the injection facility is characterized in that it further includes a water surface pressurizing unit installed inside the storage tank and capable of applying a certain pressure to the water surface of the organic acid eluent, and a freeze prevention unit that prevents freezing of the organic acid eluent stored in the storage tank and prevents freezing of a line through which the organic acid eluent flows.

In addition, the injection facility is characterized by further including a plurality of level detection sensors provided in each of the storage tanks to measure the level of the organic acid eluent and transmit the measured level to a control unit, and a control valve provided in the storage tank to control the opening and closing of the storage tank.

In addition, it is characterized by including a sealing member installed in the railway contaminated soil on top of the mobile injection well.

In addition, the water treatment device is characterized in that it continuously passes groundwater containing the heavy metal complex through a supply tank, an adsorption tank, and an adsorbent to recover the heavy metal, and then sends it to a storage tank of the injection facility so that the organic acid extractant is repeatedly reused.

A method for purifying heavy metal-contaminated soil in an unsaturated zone according to an embodiment of the present invention comprises the steps of: selecting a purification section including a heavy metal-contaminated area in an unsaturated zone among railway land; placing a movable injection well attached to gravels in the selected purification section, and then striking the upper end of the movable injection well using a vibration impact device to drive a part of the movable injection well into the ground; installing an extraction well so that a dissolution agent mixed with an organic acid and hydrogen peroxide injected from the movable injection well can flow into groundwater through a heavy metal-contaminated area above the groundwater level; injecting the dissolution agent evenly by gravity without using power into the heavy metal-contaminated area in the unsaturated zone through the movable injection well; and injecting the dissolution agent into the heavy metal-contaminated area in the unsaturated zone so that the organic acid forms a complex with the heavy metal and, at the same time, the hydrogen peroxide facilitates contact between the heavy metal and the organic acid dissolution agent, thereby increasing dissolution efficiency. And it is characterized by including a step of recovering groundwater containing the heavy metal complex compound through the extraction well and separating the heavy metal.

Embodiments of the present invention can effectively remove heavy metal pollutants distributed within an unsaturated zone by being moved and installed in railway-contaminated soil requiring rapid purification using a mobile injection well.

Embodiments of the present invention have the effect of significantly improving worker convenience by making it easier to mount and detach a mobile injection well from railway-contaminated soil.

Embodiments of the present invention change the organic acid dissolving agent to a gravity-type one without using power, so that the organic acid dissolving agent can be evenly infiltrated into the soil, and the piping configuration can be simplified.

In embodiments of the present invention, since the supply line providing the organic acid eluent and the mobile injection well are connected to each other through a separable coupler, welding is unnecessary, and this prevents problems such as leakage due to defective welding, and makes maintenance and repairs thereafter easy.

Embodiments of the present invention have the effect of preventing freezing of an organic acid dissolving agent by using a freeze-prevention means in an injection facility storing an organic acid dissolving agent at risk of freezing.

Figure 1 is a schematic diagram illustrating a system for purifying unsaturated heavy metal contaminated soil using a mobile injection device according to an embodiment of the present invention.
FIG. 2 is an enlarged drawing of a vibration striking device for driving the mobile injection well illustrated in FIG. 1 into the ground.
Figure 3a is an enlarged perspective view showing the mobile injection device illustrated in Figure 2.
Figure 3b is a cross-sectional view showing the mobile injection device illustrated in Figure 3a.
Figures 4a and 4b are front views showing a modified example of the mobile injection device illustrated in Figures 3a and 3b.
Figure 5 is a drawing for explaining the storage tank of the injection facility shown in Figure 1.
FIG. 6 is a diagram for explaining the working relationship of an unsaturated heavy metal contaminated soil purification system according to an embodiment of the present invention.
Figure 7 is a schematic diagram conceptually illustrating a cross-section of an unsaturated heavy metal contaminated soil purification system according to another embodiment of the present invention.
FIG. 8 is a schematic diagram illustrating a plan view of an unsaturated heavy metal contaminated soil purification system according to another embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

Figure 1 is a schematic diagram illustrating a system for purifying unsaturated heavy metal contaminated soil using a mobile injection device according to an embodiment of the present invention.

As illustrated in FIG. 1, the unsaturated zone heavy metal contaminated soil purification system (10) according to an embodiment of the present invention comprises: a plurality of movable injection wells (100) equipped with tapered surfaces (100a) having sharp tips so that they can be driven into railway-contaminated soil (20); an injection facility (200) connected to a manifold block (110) and a supply line (220) that protrudes when the movable injection wells (100) are driven into the ground to provide an organic acid extractant to the movable injection wells (100); a plurality of extraction wells (300) that extend to below the groundwater surface so that the organic acid extractant provided from the movable injection wells (100) can flow into the groundwater through the unsaturated zone heavy metal contaminated zone above the groundwater surface; a water treatment device (400) for pumping out and treating groundwater containing a complex compound formed by the organic acid extractant reacting with a heavy metal from the extraction wells (300); It is characterized by including a vibration impact device (500) that generates a striking force capable of striking the top of a mobile injection well (100) and driving it into railway contaminated soil (20).

The mobile injection device (100) is configured to include a manifold block (110) and a nozzle (120) so that it can be firmly fixed to the ground of railway-contaminated soil (20).

The manifold block (110) is made of a casting and is mounted on one end of the supply line (220), and the nozzle (120) has a pointed tip and is configured to be driven into the ground. That is, the tip is shaped like a pointed tip and has a tapered surface (100a), and by striking the upper side of the manifold block (110) with a vibrating striking device, the nozzle (120) is driven into the ground and the manifold block (110) can be fixed to the ground.

These mobile injection wells (100) can be fixed on gravel between railway rails (30) within a selected purification section of railway contaminated soil (20).

Here, the mobile injection well (100) is fixed on highly permeable gravels so that the organic acid extractant can stably permeate horizontally from the nozzle and slowly permeate into the heavy metal contaminated area by gravity. That is, a plurality of such mobile injection wells (100) are fixed on the upper part of the heavy metal contaminated area distributed within the unsaturated zone above the groundwater level of the railway contaminated soil (20), and the organic acid extractant is allowed to flow naturally through the nozzle (120).

Accordingly, the organic acid eluting agent can be uniformly penetrated into the heavy metal contamination area by gravity without using power through the nozzle (120) of the mobile injection device (100).

The mobile injection well (100) is connected to an injection facility (200) for supplying an organic acid eluent to the mobile injection well (100) through a supply line (220).

An injection facility (200) according to an embodiment of the present invention may be configured to include a storage tank (210) that stores an organic acid eluent provided to each of a plurality of mobile injection wells (100), a plurality of supply lines (220) that provide the organic acid eluent stored in the storage tank (210) to the plurality of mobile injection wells (100), a distributor (230) that is connected to the storage tank (210) so that the supply lines (220) can be connected, and a connection socket (600) that connects the supply lines (220) and the mobile injection well (100) to send the organic acid eluent provided from the supply lines (220) to the mobile injection well.

The organic acid extractant is a liquid containing a substance that forms a complex compound by reacting with heavy metals contained in railway contaminated soil (20).

In the unsaturated heavy metal contaminated soil purification system (10) according to an embodiment of the present invention, citric acid, which is an organic acid eluting agent, is used instead of inorganic acid eluting agents such as hydrochloric acid and sulfuric acid, which are generally used to elute heavy metals. This is because organic acid eluting agents, unlike inorganic acid eluting agents, are not chemically hazardous substances, are harmless to the human body, and are easy to manage and use.

In addition, when using inorganic acid dissolution agents, which are classified as chemical hazardous substances and chemicals that require management, various auxiliary facilities are required to prevent various chemicals from leaking out. In addition, citric acid, which is an organic acid dissolution agent, has the characteristic of having excellent dissolution efficiency for heavy metals even when used in small amounts compared to inorganic acid dissolution agents.

Meanwhile, in the unsaturated heavy metal contaminated soil purification system (10) according to the embodiment of the present invention, citric acid can be used as an organic acid elution agent and hydrogen peroxide can be used as an elution aid agent. Hydrogen peroxide is a strong oxidizing agent that rapidly oxidizes heavy metals. Accordingly, when hydrogen peroxide is added together with an organic acid, the heavy metal elution rate can be significantly increased compared to when an organic acid is used alone.

The organic acid extractant stored in the storage tank (210) is sent to the mobile injection well (100) through the supply line (220) and is directly injected into the surrounding ground from the mobile injection well (100).

A distributor (230) to which a plurality of the supply lines (220) are connected may be connected to the bottom of the storage tank (210). The distributor (230) may help supply the organic acid eluent to the plurality of supply lines (220), thereby making the organic acid eluent supply device of the supply line (220) more efficient.

The supply line (220) connected to the distributor (230) may be shaken by external impact, so it is preferable to form it as a flexible pipe (220) that can respond to such shaking.

In order to extract the organic acid extractant provided through the injection facility (200) and the mobile injection well (100), an extraction well (300) is installed adjacent to the mobile injection well (100) and extended to below the groundwater level.

The extraction well (300) is a steel pipe with a strainer at the tip and is equipped with a pump. The strainer is positioned at a deeper location than the heavy metal contaminated area containing the heavy metal contaminants to be purified, and as a result, the extraction well (300) can extract groundwater at a deeper location than the heavy metal contaminated area containing the heavy metal contaminants.

Groundwater containing heavy metals extracted from an extraction well (300) can be reused or discharged after having the heavy metals removed by a water treatment device (400).

FIG. 2 is an enlarged view showing a state in which the mobile injection well illustrated in FIG. 1 is driven into the ground by striking it with a vibration striking device, and FIG. 3 is an enlarged perspective view showing the mobile injection well illustrated in FIG. 2.

As illustrated in FIGS. 1 to 3, a vibration impact device (500) according to an embodiment of the present invention comprises a main body (510) having an L-shape, movable members (520) provided on both sides of the lower portion of the main body (510), a movable injection well impact member (530) provided at the front end of the main body (510) and guided by the main body (510) to move up and down while striking the upper end of a movable injection well (100) to generate a direct impact force capable of embedding the well into railway-contaminated soil, and a connecting member (540) that allows the movable injection well impact member (530) to be connected to the main body (510) so as to be able to move up and down.

The main body (510) is configured to have an overall L-shaped cross-section and form an exterior that supports a movable member (520), a movable injection-type impact member (530), and a connecting member (540).

A movable member (520) having stable movable force is provided on both sides of the lower portion of the main body (510). This movable member (520) may be formed as a general wheel (520) or may be formed as an infinite track structure.

The injection well impact member (530) is formed vertically at the front end of the main body, and is guided by the main body (510) to move up and down while pressurizing the movable injection well (100) to strike the upper end of the movable injection well (100) and generate a striking force that can embed it into the railway contaminated soil (20). This injection well impact member (530) may include a fork-shaped injection well impact member (530).

The connecting member (540) can be formed in various structures such that the movable injection-type striking member (530) is supported on the main body (510) and connected so as to be able to move up and down with respect to the main body (510).

Accordingly, the vibration impact device (500) according to the embodiment of the present invention can stably embed the mobile injection well (100) into the railway contaminated soil (20), and in this embedded state, the mobile injection well (100) can stably supply the organic acid eluent.

In addition, in the unsaturated heavy metal contaminated soil purification system (10) according to the embodiment of the present invention, the supply line (220) and the mobile injection well (100) can be connected to each other using a detachable connection socket (600).

In the conventional case, in order to connect the supply line (220) and the mobile injection well (100), the mobile injection well (100) was installed by welding the end of the supply line (220), but this had problems such as leakage of the organic acid eluent due to poor welding, and difficulty in subsequent maintenance and repair.

However, since the unsaturated heavy metal contaminated soil purification system (10) according to the embodiment of the present invention connects the supply line (220) and the mobile injection well (100) to each other using a detachable connection socket (600), problems such as leakage due to welding defects can be prevented, and maintenance and repairs thereafter become easier. Since it is connected in a non-welding manner, the number of assembly processes can be reduced and construction costs can be reduced.

Here, the connection socket (600) connecting the supply line (220) and the mobile injection device (100) may be configured to include a casing part (610), an elastic jig part (620) formed at the front end of the internal space of the casing part (610) to be coupled with the supply line (220), and a screw part (630) formed at the rear end of the internal space of the casing part (610).

The elastic jig part (620) can be fitted into the groove of the supply line (220) formed in the form of a flexible pipe to connect the supply line (220) and the casing part (610) of the connection socket (600). The connection assembly of the casing part (610) of the connection socket (600) and the supply line (220) is performed by pushing the supply line (220) from the outside of the casing part (610) into the internal space, and the elastic jig part (620) elastically flows so that the supply line (220) is inserted into the internal space. In the inserted state, the elastic jig part (620) is combined with the folds of the supply line (220) formed in the form of a flexible pipe, so that even if the supply line (220) is pulled from the outside, the supply line (220) does not come off from the casing part of the connection socket.

And the connecting screw surface (110) formed on the outer surface of the mobile injection device (100) can be inserted into the inner space of the casing part (610) of the connecting socket (600), and the connecting screw surface (110) of the mobile injection device (100) can be coupled to the screw part (630) formed on the inner surface of the casing part (610).

Accordingly, the mobile injection device (100) and the supply line (220) can be stably connected without being separated from each other through the connection socket (600).

Fig. 3a is an enlarged perspective view showing the mobile injection device illustrated in Fig. 2, and Fig. 3b is a cross-sectional view showing the mobile injection device illustrated in Fig. 3a.

As illustrated in FIGS. 1 to 3b, a mobile injection device (100) according to an embodiment of the present invention may include an organic acid elution agent manifold (100) for distributing and discharging a flow of an organic acid elution agent provided from a supply line (220) of an injection facility (200) throughout the entire heavy metal contamination area.

The manifold block (110) of the organic acid eluent manifold (100) may generally have a rectangular hexahedral shape. In other embodiments, the manifold block (110) may have a cylindrical shape, an oval cross-section, a diamond-shaped cross-section, a triangular cross-section, a square or rectangular cross-section, etc.

An inlet (110a) is formed at the top of the manifold block (110) to be connected to the supply line (220) of the injection facility (200) and to receive an organic acid eluent. The organic acid eluent supplied by the supply line (220) of the injection facility (200) can be provided to the organic acid eluent manifold (100) through the inlet (110a) and discharged through a plurality of nozzles (120).

Meanwhile, handles (130) may be provided on both sides of the rectangular hexahedral manifold block (110) to enable workers to easily move the movable injection well (100) or organic acid eluent manifold (100).

The nozzle (120) is formed to extend radially outward from the manifold block (110). The manifold block (110) includes a plurality of openings (110b), each corresponding to a nozzle (120).

The inlet end of the nozzle (120) is welded to the manifold block (110) through TIG welding or a similar attachment process, so that the organic acid eluent flowing into the manifold block (110) of the organic acid eluent manifold (100) through the inlet (110a) can flow through the opening of the manifold block (110) and into each nozzle (120).

That is, each nozzle (120) and each opening (110b) on the manifold block (110) form a path through which the organic acid eluent within the manifold block (110) can be emitted from the organic acid eluent manifold (100).

A tapered surface (100a) having a sharp shape is formed at the tip of the nozzle (120) so that it can be embedded in railway-contaminated soil, and a plurality of first injection holes (120a) and second injection holes (120b) are formed radially on the outer surface of the tapered surface (100a) and the outer surface of the other end that is not tapered and is parallel so that an organic acid eluent supplied through a supply line (220) and a manifold block (110) can penetrate by gravity.

Although the embodiment of the mobile injection unit (100) illustrated in the drawing includes five nozzles (120), various embodiments may provide any suitable number of nozzles (120). For example, certain embodiments may include from three to ten or more nozzles (120). The nozzles (120) may be spaced apart along the longitudinal direction (L) of the manifold block (110). The distance between adjacent nozzles (120) may be the same or may vary.

The nozzles (120) of the mobile injection well (100) each have a penetration range of a certain radius and are spaced apart from each other at a higher position than the heavy metal contamination area, and the organic acid extractant provided from the mobile injection well (100) can penetrate into the interior of the railway-contaminated soil (20).

At this time, the organic acid extractant stably penetrates from above the railway contaminated soil (20) through the first and second injection holes (120a, 120b) of the movable injection well (100) toward the heavy metal contamination area without missing any point due to gravity, so that the organic acid extractant can be evenly penetrated into the railway contaminated soil (20) without using power.

In addition, by using a mobile injection well (100) to be quickly moved to and installed in railway-contaminated soil (20) requiring purification, heavy metal pollutants distributed within the unsaturated zone can be effectively removed, and the mobile injection well (100) can be more easily installed and removed from railway-contaminated soil (20), thereby significantly improving worker convenience.

In addition, the organic acid eluting agent can be evenly penetrated into the railway contaminated soil (20) while being diffused by the first and second injection holes (120a, 120b) of the mobile injection well (100). Therefore, the organic acid eluting agent injected simultaneously from a plurality of mobile injection wells (100) can pass through the entire portion including the heavy metal contaminated area of the railway contaminated soil (20) while simultaneously removing heavy metals from the entire area of the heavy metal contaminated area.

Meanwhile, as shown in FIGS. 4a and 4b, the mobile injection device (100) according to the embodiment of the present invention may have a plurality of slits (120b) formed instead of a plurality of second injection holes (120b). The positions and numbers of the slits (120b) formed in the nozzle (120) are not limited, and a desired number may be formed at a desired position. For example, slits (120b) may be formed at predetermined intervals on the outer surface of the tip tapered surface (100a) of the nozzle (120) and the outer surface of the other end to allow the organic acid eluent to penetrate by gravity.

Figure 5 is an enlarged drawing of the injection facility of the unsaturated heavy metal contaminated soil purification system illustrated in Figure 1.

As illustrated in FIGS. 1 and 5, the injection facility (200) of the unsaturated heavy metal contaminated soil purification system according to an embodiment of the present invention may further include a water surface pressurization unit (240) installed inside a storage tank (210) and capable of applying a certain pressure to a water surface of an organic acid extractant, and a freeze prevention unit (250) that prevents freezing of the organic acid extractant stored in the storage tank (210) and prevents freezing of a line through which the organic acid extractant flows.

The water surface pressurization unit (240) of the injection facility according to an embodiment of the present invention may have a function of applying a constant pressure to the water surface of the organic acid eluent by using a pressure contact part (241) that is installed inside the storage tank (210) and is installed to be able to move up and down inside the storage tank (210). In this way, by maintaining the pressure inside the organic acid eluent storage tank (210) constant, the discharge pressure of the organic acid eluent outside the organic acid eluent storage tank (210) can be maintained constant.

The sleep pressurization unit (240) of the injection facility (200) according to this embodiment of the present invention may be configured to include a pressurization contact part (241), an elevating moving part (242), and a power providing part (243).

The pressurized contact portion (241) can be installed so that its lower surface comes into contact with the water surface of the organic acid eluent stored in the storage tank (210) and applies a certain pressure to the water surface of the organic acid eluent.

The lifting moving part (242) is coupled to the upper surface of the pressurized contact part (241) and can transmit power generated from the power providing part (243) to the pressurized contact part (241).

The power supply unit (243) is installed at the inner upper part of the storage tank (210) and generates power to move the pressurized contact unit (241) upward or downward, and can transmit this power to the pressurized contact unit (241) through the lifting and lowering unit (242).

Accordingly, the injection facility (200) according to the embodiment of the present invention may be positioned at the bottom of the organic acid eluent storage tank (210) so that the organic acid eluent slowly flows toward the heavy metal contamination area from the distributor (230), the supply line (220), and the mobile injection well (100) in a natural flow manner.

In particular, the mobile injection well (100) is connected to the storage tank (210) of the organic acid eluent through a distributor (230) and a supply line (220), and is located below the storage tank (210) so that the organic acid eluent flows downward through the mobile injection well (100) in a natural downward manner by gravity, thereby providing a path for natural transport of the organic acid eluent even in a situation where there is no separately installed power.

The freeze prevention unit (250) according to an embodiment of the present invention may be configured to include an air supply unit (251), a stirring blade (252), and a heating heater (253) provided in an organic acid extractant storage tank (210).

The air supply unit (251) can supply air to the liquid organic acid eluent stored in the storage tank (210), thereby causing the organic acid eluent to flow in the storage tank (210).

The stirring blade (252) can prevent freezing by rotating the organic acid extractant stored in the storage tank (210). The stirring blade (252) can be formed by a plurality of rotating blades (252) provided inside the storage tank (210) of the injection device (200). The plurality of rotating blades (252) can include a shape that is rotated by a predetermined angle along the height direction of the rotating blades in order to obtain a more easily stirring force.

The heating heater (253) may be provided at the bottom of the storage tank (210) in a heating wire manner, but this is only a preferred embodiment, and may include any heating means for preventing freezing of the organic acid eluent located inside the storage tank (210).

Meanwhile, the injection facility (200) according to a preferred embodiment of the present invention further includes a plurality of water level detection sensors (260) provided in each of the storage tanks (210) to measure the water level of the organic acid eluent and transmit the measured water level to a control unit (not shown), and a control valve (270) provided in each of the storage tanks (210) to control the opening and closing of the storage tank (210). When the water level transmitted from the water level detection sensors (260) is below a preset value, the control unit (not shown) can close the control valves (270) installed in each of the storage tanks (210) and provide an organic acid eluent supply alarm to an operator.

At this time, a plurality of water level detection sensors (260) can be installed at different heights with a certain interval inside each storage tank (210). When the water level received from the water level detection sensor (260) is below a preset value, the control unit (not shown) closes the control valve (270) of the storage tank (210) and provides a supply alarm of an organic acid extractant that can be recognized in the surroundings, thereby inducing a worker in the surroundings to supply an organic acid extractant to the storage tank (210).

FIG. 6 is a diagram for explaining the working relationship of an unsaturated heavy metal contaminated soil purification system according to an embodiment of the present invention.

As illustrated in FIGS. 1, 2, and 6, in the unsaturated heavy metal contaminated soil purification system (10) according to an embodiment of the present invention, first, a purification section is selected from among railway contaminated soil (20), and once the purification section is selected, a movable injection well (100) can be installed along the railway rail (30) in the space between the railway rails (30). At this time, the movable injection well (100) is quickly moved to the section requiring purification, and then, by utilizing a vibration impact device (500), the tapered surface (100a) of the movable injection well (100) having a sharp tip can be driven into the railway contaminated soil (20).

The vibration impact device (500) generates a striking force that can strike the manifold block (110) at the top of the mobile injection well (100) to drive the tapered surface (100a) into the railway contaminated soil (20). After the mobile injection well (100) is driven in by the vibration impact device (500), an organic acid eluting agent mixed with citric acid and hydrogen peroxide is prepared and the organic acid eluting agent is injected into the heavy metal contamination area (X) of the railway contaminated soil (20) contaminated with heavy metals.

These organic acid dissolving agents form complexes with heavy metals present in the heavy metal contamination area (X) of the railway contaminated soil (20). That is, heavy metals present in an ionic state in the heavy metal contamination area (X) of the railway contaminated soil (20) react with the organic acid dissolving agent to form complexes, thereby being removed from the heavy metal contamination area (X) of the railway contaminated soil (20).

Generally, the higher the concentration of the organic acid eluent in the composition being injected, the higher the removal efficiency of heavy metals. However, a concentration in the range of 0.1 M to 1 M is preferably appropriate. This is because if the concentration of the organic acid eluent is less than 0.1 M, the heavy metal removal efficiency cannot be maintained at a desirable level, and on the other hand, if it exceeds 1 M, the chemical cost is excessively required and it can be harmful to the natural environment.

In addition, hydrogen peroxide included in the organic acid dissolution agent acts as an oxidizing agent that rapidly oxidizes heavy metals present in the heavy metal contamination area (X) of the railway polluted soil (20). Such hydrogen peroxide can increase the efficiency of separating heavy metals from fine soil due to bubble entrainment caused by bubbles generated when rapidly decomposing upon reaction with heavy metals, or can increase the dissolution efficiency by facilitating contact between the heavy metal and the organic acid dissolution agent. In this way, by using hydrogen peroxide as a dissolution aid, the dissolution efficiency of heavy metals can be greatly increased.

As described above, when the organic acid dissolving agent according to the embodiment of the present invention is injected into railway-contaminated soil (20) contaminated with heavy metal pollutants, hydrogen peroxide is rapidly decomposed upon reaction with the heavy metal, and water joins the groundwater flowing in the railway-contaminated soil (20) or is used in various ways in the railway-contaminated soil (20), and the organic acid dissolving agent forms a complex with the heavy metal and flows into the groundwater in the railway-contaminated soil (20).

Next, groundwater containing a complex compound is sent to a water treatment device (400) using a motor pump (310) that can draw up groundwater through an extraction well (300) installed in the groundwater. In the water treatment device (400), the complex compound is decomposed and separated into heavy metals and an organic acid extractant, and the organic acid extractant can be reused in the purification method or the heavy metals can be recovered.

Therefore, the unsaturated zone heavy metal contaminated soil purification system (10) according to an embodiment of the present invention effectively removes heavy metal contaminants distributed in the unsaturated zone by quickly moving and installing a plurality of mobile injection wells (100) to railway contaminated soil (20) requiring purification, and also provides convenience to workers by making it easier to install and detach the mobile injection wells (100) from the railway contaminated soil (20).

Next, another embodiment of the present invention will be described with reference to Fig. 7. When the same components as those in the above-described embodiment are indicated, the same reference numerals are given and the description thereof is omitted. Fig. 7 is a schematic diagram conceptually showing a cross-section of an unsaturated heavy metal contaminated soil purification system according to another embodiment of the present invention.

As shown in FIG. 7, the unsaturated zone heavy metal contaminated soil purification system (10') according to another embodiment of the present invention comprises: a mobile injection well (100) equipped with a tapered surface (100a) having a sharp tip so that it can be driven into railway-contaminated soil (20); an injection facility (200) connected to a manifold block (110) and a supply line (220) that protrudes when the mobile injection well (100) is driven into the ground to provide an organic acid extractant to the mobile injection well (100); an extraction well (300) that extends to below the groundwater surface so that the organic acid extractant provided from the mobile injection well (100) can flow into the groundwater through the unsaturated zone heavy metal contaminated area above the groundwater surface; and a water treatment system for pumping up and treating groundwater containing a complex compound formed by the organic acid extractant reacting with a heavy metal from the extraction well (300). It is characterized by including a device (400), a vibration striking device (500) for striking the upper part of a mobile injection well (100) and driving it into the railway contaminated soil (20), and an airtight member (700) installed in the railway contaminated soil on the upper part of the mobile injection well (100).

According to another embodiment of the present invention, a sealing member (700) may be formed of a concrete panel (700) and may be placed on a gravel layer covering a mobile injection well (100). Since the concrete panel (700) has low permeability compared to railway-contaminated soil (20), it is difficult for rainwater to mix with the organic acid extractant injected from the mobile injection well (100). Accordingly, it is possible to suppress the concentration of decomposed substances or the temperature of the organic acid extractant from decreasing. In addition, it is possible to suppress the volatilization of the organic acid extractant. Therefore, it is possible to maintain the concentration of decomposed substances in the organic acid extractant or the temperature of the organic acid extractant at an appropriate value.

Meanwhile, in this embodiment, a sealing member (700) is installed to prevent rainwater from mixing with the organic acid eluent, but the embodiment of the present invention is not limited thereto. For example, the sealing member (700) may be installed to prevent the organic acid eluent from being affected by the outside temperature. At this time, by forming the sealing member (700) with an insulating material such as Styrofoam, it is possible to prevent the heated organic acid eluent from being cooled by the outside air in winter.

Therefore, the unsaturated heavy metal contaminated soil purification system (10) according to another embodiment of the present invention can install a sealing member (700) on top of a movable injection well (100) for railway contaminated soil (20) to prevent rainwater from mixing with the organic acid extractant or to install the organic acid extractant so that it is not easily affected by the outside temperature.

Next, another embodiment of the present invention will be described with reference to Fig. 8. When the same components as those in the above-described embodiment are indicated, the same reference numerals are given and the description thereof is omitted. Fig. 8 is a schematic diagram conceptually showing a plan of an unsaturated heavy metal contaminated soil purification system according to another embodiment of the present invention.

As illustrated in FIG. 8, an unsaturated zone heavy metal contaminated soil purification system (10'') according to another embodiment of the present invention comprises: a movable injection well (100) equipped with a tapered surface (100a) having a sharp tip so that it can be driven into railway-contaminated soil (20); an injection facility (200) connected to a manifold block (110) and a supply line (220) that protrudes when the movable injection well (100) is driven into the ground to provide an organic acid eluent to the movable injection well (100); an extraction well (300) that extends to below the groundwater surface so that the organic acid eluent provided from the movable injection well (100) can flow into the groundwater through the unsaturated zone heavy metal contaminated zone (X) above the groundwater surface; and a water treatment system for pumping up and treating groundwater containing a complex compound formed by the organic acid eluent reacting with a heavy metal from the extraction well (300). The device (400') and the vibration striking device (500) for striking the top of the mobile injection well (100) and driving it into the railway contaminated soil (20), in particular, the water treatment device (400') of the unsaturated heavy metal contaminated soil purification system (10) according to another embodiment of the present invention provides a system (400') for recovering heavy metals and reusing an organic acid extractant.

The extraction well (300) is connected to a supply tank (430) and a treatment tank (420) through a valve (410). The supply tank (430) is provided with a means for measuring the concentration of residual contamination contained in groundwater, and this measurement is transmitted to the valve (410) so that the connection of the extraction well (300) is switched to either the supply tank (430) or the treatment tank (420).

Groundwater with a residual pollutant concentration higher than the standard is introduced into a treatment tank (420) through a valve (410). An ion exchange membrane or an electrodialysis means is provided in this treatment tank (420), and residual pollutants can be separated from the wash water by ion exchange or electrodialysis to purify the groundwater. Groundwater discharged from this treatment tank (420) can be introduced into a supply tank (430). Meanwhile, groundwater with a residual pollutant concentration lower than the standard can be directly introduced into the supply tank (430) by switching the valve (410).

Meanwhile, groundwater containing heavy metal complexes is introduced into an adsorption tank (440), where the heavy metals are removed by adsorption onto an adsorbent. The adsorption tank (440) can be divided into two interior parts, and the downstream part can be filled with an adsorbent (450), so that groundwater flowing into the upstream adsorption tank (440) can be arranged to continuously pass through the adsorbent (450).

According to this structure, the contact time between groundwater and the adsorbent (450) is prolonged, and replacement of the adsorbent (450) is also easy.

Therefore, the water treatment device (400') of the unsaturated heavy metal contaminated soil purification system (10'') according to another embodiment of the present invention can provide a system (400') for repeatedly reusing the organic acid extractant to remove the heavy metal contaminated area by continuously passing groundwater containing heavy metal complexes through a supply tank (430), an adsorption tank (440), and an adsorbent (450) to recover heavy metals and then sending the recovered groundwater to a storage tank (210) of an injection facility (200).

As described above, it can be seen that the unsaturated zone heavy metal polluted soil purification system according to the embodiment of the present invention is based on the basic technical idea of rapidly moving and installing a movable injection well in the unsaturated zone of railway polluted soil to evenly infiltrate an organic acid extractant by gravity to rapidly remove heavy metal pollutants. Therefore, it goes without saying that many other modifications are possible for those skilled in the art within the scope of the basic technical idea of the present invention.

10...Unsaturated heavy metal contaminated soil purification system 100...Mobile injection well
110... Manifold Block 120... Nozzle
200...injection equipment 210...storage tank
220...supply line 230...distributor
240...Sleep pressure unit 250...Freeze protection unit
260...water level detection sensor 300...extraction well
400...Water treatment device 500...Vibrating impact device
510...body 520...moving member
530...Mobile injection nozzle striking member 540...Connecting member
600...connection socket 700...secret absence

Claims (10)

A number of mobile injection wells equipped with tapered surfaces with pointed tips to enable them to be driven into railway-contaminated soil,
An injection facility for providing an organic acid eluent to the above-mentioned mobile injection well by connecting the manifold block and supply line to the above-mentioned mobile injection well in a protruding state while the above-mentioned mobile injection well is embedded in the ground,
A number of extraction wells are installed to extend below the groundwater level so that the organic acid extractant provided from the above-mentioned mobile injection well can flow into the groundwater through the heavy metal contamination zone of the unsaturated zone above the groundwater level,
A water treatment device for pumping groundwater containing a complex compound formed by the reaction of the organic acid extractant with a heavy metal from the extraction well and treating the same,
A vibration impact device is included that generates a striking force that can strike the manifold block at the top of the above-mentioned mobile injection device to embed the above-mentioned tapered surface into the above-mentioned railway-contaminated soil.
The above mobile injection device includes an organic acid elution agent manifold for distributing the flow of the organic acid elution agent provided from the supply line to the heavy metal contamination area without using power and discharging it evenly by gravity.
The above injection facility includes a storage tank storing the organic acid eluent, and a water surface pressurization unit installed to apply a constant pressure to the water surface of the organic acid eluent and to maintain the discharge pressure of the organic acid eluent constant.
The above-mentioned water surface pressurization unit is characterized by including a pressurization contact part installed so as to apply a certain pressure to the water surface of the organic acid eluent by contacting the lower surface thereof with the water surface of the organic acid eluent, a power providing part installed at the upper inner part of the storage tank to generate power to move the pressurization contact part upward or downward, and an elevating moving part coupled to the upper surface of the pressurization contact part to transmit the power generated by the power providing part to the pressurization contact part. The unsaturated heavy metal contaminated soil purification system. In the first paragraph,
The above organic acid eluent manifold is,
A manifold block through which an organic acid eluent is delivered through an inlet connected to the above supply line,
An unsaturated heavy metal contaminated soil purification system characterized by including a plurality of nozzles that are formed to extend radially outwardly from the manifold block and are spaced apart from each other along the length of the manifold block. In the first paragraph,
The above vibration striking device is,
A body having an L shape,
A moving member provided on both sides of the lower part of the above main body,
A movable injection nozzle striking member provided at the tip of the above main body and guided by the above main body to move up and down and strike the upper end of the movable injection nozzle,
An unsaturated heavy metal contaminated soil purification system characterized in that the above-mentioned mobile injection device impact member includes a connecting member that allows the mobile injection device to be vertically connected to the main body. In the first paragraph,
The above injection facility,
A plurality of supply lines in the form of flexible pipes that supply the organic acid extractant stored in the above storage tank to a plurality of movable injection wells,
An unsaturated heavy metal contaminated soil purification system further characterized by including a distributor connected to the storage tank so that the plurality of supply lines can be connected. In paragraph 4,
An unsaturated heavy metal contaminated soil purification system further characterized by including a connecting socket for connecting the above-mentioned mobile injection device and the supply line to each other. In the first paragraph,
The above injection facility further includes a freeze prevention unit that prevents freezing of the organic acid eluent stored in the storage tank and prevents freezing of the line through which the organic acid eluent flows.
A system for purifying unsaturated heavy metal contaminated soil, characterized in that the above-mentioned freeze-prevention unit includes an air supply unit for supplying air to a liquid organic acid extractant stored in the storage tank, a stirring blade for rotating the organic acid extractant stored in the storage tank, and a heating heater provided in a heating wire manner at the bottom of the storage tank. In the first paragraph,
The above injection facility,
A plurality of water level detection sensors provided in each of the above storage tanks to measure the water level of the organic acid extractant and transmit it to the control unit,
A system for purifying unsaturated heavy metal contaminated soil, characterized in that it further includes a control valve provided in the storage tank and controlling the opening and closing of the storage tank. In the first paragraph,
An unsaturated heavy metal contaminated soil purification system characterized by including an airtight member installed in the railway contaminated soil above the above mobile injection well. In the first paragraph,
The above water treatment device,
A system for purifying unsaturated heavy metal-contaminated soil, characterized in that the groundwater containing the heavy metal complex is continuously passed through a supply tank, an adsorption tank, and an adsorbent to recover the heavy metal, and then sent to a storage tank of the injection facility so that the organic acid extractant is repeatedly reused. delete

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