JP2008029935A - Method for arranging cleaning agent in contaminated soil, and method for cleaning contaminated soil and/or ground water in situ - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for arranging a cleaning agent in contaminated soil where a mixed cleaning agent of a cleaning agent and granular matter for percolation can be arranged at the deepest part of the dug part provided in contaminated soil without uneven mixing, and to provide a method for cleaning contaminated soil and/or ground water in situ. <P>SOLUTION: A hole 2 is formed as a dug part in a foundation 1. The hole 2 is dug so as to be deeper than the level of ground water. A mixed cleaning agent 6 such as iron powder mixed sand is fed to a bucket 4 by a power shovel 5. The bucket 4 is lowered to the deepest part of the hole 2. When the bucket 4 reaches the hole bottom 2a, a lock mechanism is made into a lock release state. Then, when the bucket 4 is gradually pulled up, a bottom cover 4a starts to be opened, and the mixed cleaning agent 6 in the bucket 4 is released from the bucket 4 to the bottom part of the hole 2. Further, the bucket 4 is pulled up, thus the whole of the mixed cleaning agent 6 is released. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a technique for purifying soil and / or groundwater contaminated with a chemical substance with a purifier in situ.

  As a method for purifying soil and groundwater contaminated with an organic chlorine-based compound in situ, for example, as disclosed in JP-A-10-71386 and JP-A-10-263522, an organic chlorine-based compound is placed at a predetermined position in the contaminated soil. There is known a method of forming a dispersed layer of metallic iron powder for purifying the metal. As a method for forming such a purifier dispersion layer, a casing excavation method, an open-cut method, a mud excavation method, and the like are used.

  When such a purification agent dispersion layer is formed, the purification metal powder may be used alone, or the purification metal powder and the water-permeable granular material may be mixed and used as a mixed purification agent. This water-permeable granular material is used to ensure water permeability in a filled state, or to adjust the amount of metal powder for purification that is added depending on the purification capacity required for each site.

  When using the water-permeable granular material, the mixing ratio of the metal powder for purification and the water-permeable granular material must be within a certain range in any part of the dispersion layer when the dispersion layer is formed in the ground. . This is because if there is uneven mixing, the contaminated soil and contaminated groundwater cannot be efficiently purified, resulting in an extended purification period.

However, the shape of the metal powder for purification and the granular material for water permeable may be greatly different, and in that case, unevenness occurs in the mixing of the metal powder for purification and the granular material for water permeable during construction to be mixed and filled. There's a problem. In particular, when a drilling part, for example, a borehole, is provided deeper than the groundwater level, and when a cleaning agent composed of a mixture of metal powder for purification and water-permeable granular material is injected into the drilling part from the ground, the water accumulated in the drilling part (groundwater) When the mixture settles inside, the two separate from each other due to the difference in specific gravity between the metal powder and the water-permeable granular material, resulting in large unevenness in mixing.
JP-A-10-71386 Japanese Patent Laid-Open No. 10-263522

  The present invention solves the above-mentioned problems of the prior art, and a purification agent arrangement method capable of arranging a mixed purification agent of a purification agent and a water-permeable granular material in the deepest part of an excavation part provided in contaminated soil without mixing unevenness. And an in-situ purification method for contaminated soil and / or groundwater.

  The purification agent disposing method of the present invention is a method of disposing a mixed purifying agent containing a purifying agent and water-permeable granular material at the deepest part of a soil excavation part, wherein the mixed purifying agent is placed in a container whose bottom can be opened and closed. The mixed purifier is disposed in the excavation part by lowering the container to the deepest part of the excavation part and then releasing the mixed purifier by opening the bottom of the container. It is.

  In the in-situ purification method for contaminated soil and / or groundwater of the present invention, an excavation part is provided in the contaminated soil, and a mixed purification agent containing a purification agent and water-permeable granular material is disposed at the deepest part of the excavation part, and the mixing A method for in-situ purification of contaminated soil and / or groundwater that purifies soil and / or groundwater with a purifier, wherein the mixed purifier is contained in a container whose bottom can be opened and closed, and the container is placed at the deepest of the excavation part. The mixed cleaning agent is disposed in the excavation part by lowering the container to the bottom and then releasing the mixed cleaning agent by opening the bottom of the container.

  In the present invention, the mixed purification agent of the purification agent and the water-permeable granular material is accommodated in the container and lowered to the deepest part of the excavation part, and then the bottom of the container is opened to release the mixed purification agent from the container to the deepest part. Therefore, even when the excavation part is provided deeper than the groundwater level, the mixed purification agent does not settle down in the water in the excavation part, and the separation phenomenon of the mixed purification agent due to this sedimentation fall is prevented. The Thereby, it becomes possible to purify contaminated soil and / or groundwater efficiently.

  Hereinafter, the present invention will be described in more detail.

  In the present invention, an excavation part is provided in the contaminated soil, and a mixed purification agent containing the purification agent and the water-permeable granular material is disposed at the deepest part of the excavation part.

  Examples of pollutants that contaminate the soil include organochlorine compounds, alkalis, fluorine, and heavy metals.

  Examples of the purifying agent include metal powder for purification if an organic chlorine compound is used, acid clay if alkali is used, magnesium oxide if fluorine is used, chelate, iron salt, aluminum salt if heavy metal is used. However, the present invention is not limited to these, and various purification agents can be employed depending on the purification target. For example, iron is exemplified as the metal powder for purification, and iron oxide, reduced iron, alloy, and the like are preferable, but reduced iron is more preferable. When the soil contains a plurality of types of pollutants, a plurality of these cleaning agents can be mixed and used, or after one or a plurality of types of mixed cleaning agents are arranged at the deepest part of the excavation part, another type of mixing agent is mixed thereon. A purifier may be placed.

  The shape of the purifier is not particularly limited, but for example, a coarse particle having a particle diameter of 0.1 to 2 mm that does not hinder the flow of groundwater is desirable.

There are no particular problems with the water-permeable granular material as long as it is a material that is not environmentally problematic, and a material having a water permeability coefficient in the filled state of the order of 10 ⁻² to 10 ⁻³ cm / s, such as sand or gravel, is preferably used. it can. The mixing ratio of the purifying agent and the water-permeable granular material is preferably about 1: 9 to 1: 0.1 in volume ratio, but is not limited thereto.

  The shape of the excavation part may be a hole shape obtained by excavating soil or a groove shape in which excavation holes are formed in parallel. The hole is preferably formed by boring, but may be formed by a drilling bucket or the like. The diameter of the hole is preferably about 200 to 3000 mm, but is not limited thereto. The present invention is suitable for application when the excavation part is formed deeper than the groundwater level and the groundwater is stored in the lower part of the excavation part.

  As a container, the mixed purifying agent can be stored and held without leaking, and mixing unevenness does not occur in the stored mixed purifying agent until reaching the deepest part of the excavation part, and when the deepest part is reached, the bottom opens and the mixed purifying agent is removed. Any structure can be used as long as it can be released.

  Hereinafter, with reference to FIG. 1 and FIG. 2, an example of the method of arrange | positioning mixed purification agent in the deepest part of an excavation part is demonstrated.

  FIGS. 1 (a) and 1 (b) are cross-sectional views showing the operation of placing the mixed purification agent in the excavation part by the method according to the embodiment.

  As shown in FIG. 1 (a), a hole 2 is formed in the ground 1 as an excavation part. This hole 2 is dug deeper than the groundwater level. In this embodiment, the hole 2 is excavated by the all casing method.

  In FIG. 1 (a), a bucket 4 is suspended as a container at the lower end of a wire rope that hangs down from a crane of a crane 3. The bucket 4 has a bottomed cylindrical shape with an open top, and is a bottom-opening type bucket having a bottom lid 4a that can be opened and closed at the bottom as shown in FIG. The bucket 4 has a lock mechanism (not shown) for locking the bottom lid 4a in a closed state, and an unlock lever 4b for unlocking the lock mechanism. The unlock lever 4b protrudes downward from the bottom surface of the bucket 4 in the locked state, and is configured to be pushed upward when the bucket 4 reaches the hole bottom 2a to bring the lock mechanism into an unlocked state.

  As shown in FIG. 1 (a), a mixed purification agent 6 such as iron powder mixed sand is supplied to the bucket 4 by a power shovel 5. Next, the crane 3 is self-propelled and boom-turned so that the bucket 4 is placed in the hole 2, and then the wire rope is sent out as shown in FIG. Descent to

  When the bucket 4 reaches the hole bottom 2a, the unlock lever 4b is pushed up against the hole bottom 2a as shown in FIG. 2B, and the lock mechanism is unlocked. Therefore, when the bucket 4 is gradually pulled up as shown in FIG. 2 (c), the bottom cover 4a is opened, and the mixed purification agent 6 in the bucket 4 is discharged from the bucket 4 to the bottom of the hole 2. When the bucket 4 is further lifted, all the mixed purification agent 6 in the bucket 4 is released.

  As described above, the mixed purification agent 6 is gradually discharged from the bucket 4 settled on the hole bottom 2a to the hole bottom 2a, so that the mixed purification agent 6 does not settle and fall in the ground water accumulated in the hole 2. . For this reason, iron powder and sand of the mixed purification agent are not separated. As a result, the contaminated soil and groundwater are purified efficiently.

  In addition, an experimental example to confirm that iron powder and sand do not separate even when iron powder mixed sand is discharged from the bottom of the container to the water bottom, and a comparison experiment showing that separation occurs when iron powder mixed sand is introduced from the water surface An example is shown below.

[Experimental example]
(1) As shown in FIG. 3 (a), a water tank (height 300 mm, width 300 mm, length 300 mm) 11 was set in a pool 10 having a depth of 1 m.
(2) As shown in FIG. 3 (b), iron powder and sand are mixed in the same volume in a container (height 100 mm, width 100 mm, length 100 mm) 12 whose bottom surface can be opened and closed. A mixed purification agent 6 made of iron powder mixed sand was filled. In addition, the average particle diameter of iron powder is 0.5 mm, and the average particle diameter of sand is 1.0 mm.
(3) As shown in FIG. 3 (c), the container 12 was settled on the bottom surface of the water tank 11.
(4) Next, as shown in FIG. 3 (d), the bottom of the container 12 was opened and the container 12 was pulled up, and the mixed purification agent 6 was caused to flow out of the container 12 into the water tank 11.
(5) The procedures (2) to (4) were repeated, and the water purification tank 6 was filled with the mixed purification agent 6 made of iron powder mixed sand.
(6) The water tank 11 was taken out from the pool 10, iron powder mixed sand was collected from 10 locations in the water tank 11, and the volume was measured by magnetically selecting the iron powder and sand. It was found that the volume ratio of iron powder to sand was almost equal between the bottom surface and the bottom surface, and the mixture could be filled without uneven mixing.

  In addition, the 1st-4th corner of Table 1 means the four corners in the water tank 11.

[Comparative experiment example]
In the state of Fig. 3 (a), the iron powder mixed sand was gently poured from the water surface until the water tank 11 was full.

  The water tank 11 was taken out from the pool 10, and iron powder mixed sand was collected from 10 locations in the water tank, and the volume was measured by magnetically selecting the iron powder and sand. It was found that the volume ratios of the powder and sand were different and separated during filling, resulting in mixing unevenness.

It is sectional drawing which shows the iron powder mixed sand filling procedure by the bottom opening bucket in the field. It is action | operation explanatory drawing of a bottom opening bucket. It is sectional drawing which shows the procedure of an experiment example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ground 2 Hole 3 Crane truck 4 Container 5 Excavator 6 Mixed cleaning agent

Claims (3)

It is a method of arranging a mixed purification agent containing a purification agent and water-permeable granular material in the deepest part of the soil excavation part,
The mixed purification agent is contained in a container whose bottom can be opened and closed, the container is lowered to the deepest part of the excavation part, and then the bottom of the container is opened to release the mixed purification agent, whereby the mixed purification agent is released into the excavation part. A method for disposing a purification agent in contaminated soil, characterized by disposing a mixed purification agent. A contaminated soil having an excavation part in the contaminated soil, a mixed purification agent including a purification agent and a water-permeable granular material disposed in the deepest part of the excavation part, and purifying the soil and / or groundwater with the mixed purification agent and / or Or an in-situ purification method of groundwater,
The mixed purification agent is accommodated in a container whose bottom can be opened and closed, the container is lowered to the deepest part of the excavation part, and then the bottom part of the container is opened to release the mixed purification agent, whereby the mixed purification agent is released into the excavation part. An in-situ purification method for contaminated soil and / or groundwater, wherein a mixed purification agent is disposed.   The in-situ purification method for contaminated soil and / or groundwater according to claim 2, wherein the excavation part is provided deeper than the groundwater level.

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