JP2002136963A - Decontamination method for contaminated soil and separator used for it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a decontamination method for contaminated soil which can reduce the cleaning cost of the contaminated soil by improving its washing efficiency. SOLUTION: Earth and sand B of a predetermined particle diameter or above from which contaminants, such as oils, can be separated easily are classified beforehand from earth and sand to which the contaminants stick by a sorter 1. Water is added to earth and sand A produced by classifying and removing the earth and sand B of the predetermined particle diameter or above, and then they are introduced into a washer 3. Contaminants D which stick to the surfaces of the earth and sand B are desorbed by friction between the earths and sands, and the like in the washer 3. Water containing the earth and sand D and the contaminants D is introduced in to a separating device 4 equipped with a separating tank 41 filled with water, a vibrating screen 42, and an air supply means 43. In the separating tank 41 of the separating device 4, the earth and sand A are vibrated and at the same time, sprayed with bubbles to be precipitated, thereby separating the earth and sand A from the contaminants D.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for purifying contaminated soil, which can improve the cleaning efficiency and reduce the cost for purifying contaminated soil, and to a separation apparatus used therefor.

[0002]

2. Description of the Related Art In recent years, it has become evident that the soil of various manufacturing plants and their former sites has been contaminated with contaminants such as oil, which has become a social problem. In addition, oil and fuel oil spilled due to marine accidents such as tankers, seashore soil contaminated by waste oil illegally dumped from ships, and soil (including excavated soil) to which crude oil from crude oil mining areas has adhered, There was no appropriate purification method in relation to cost and the like.

[0003]

From such a background,
It is desired to establish a technique for enabling the reuse of land by removing contaminants from contaminated soil, protecting the natural environment, and reusing sediment from which contaminants have been removed.

[0004] Incidentally, as one of the methods for purifying contaminated soil containing oil, there is a soil washing method. However, conventionally proposed soil washing methods have a high concentration of contaminants and an oil containing heavy oil or tar. In the case of, in order to remove contaminants attached to the surface of the earth and sand, it was necessary to use a large amount of water, go through multiple washing steps, and use a cleaning aid such as a surfactant. . Therefore, in such a soil cleaning method, in addition to the equipment cost, the cost of water treatment costs, the cost of cleaning aids such as surfactants, and the like, the cost of treatment increases, and the practical use is poor. there were.

The present invention has been made in consideration of the problems of the above-mentioned conventional method for cleaning contaminated soil, and in particular, in view of the problems of the soil cleaning method, and has been made to improve the cleaning efficiency and reduce the cost of cleaning contaminated soil. It is an object of the present invention to provide a method for purifying water and a separation device used for the method.

[0006]

In order to achieve the above object, a method for purifying contaminated soil according to the present invention comprises a method for purifying contaminants such as oil, which has a predetermined particle size or more, from which the contaminants are easily separated in advance. Is classified by a sorter, and the soil having a predetermined particle size or more is classified and removed, and added to the soil, introduced into the washing machine, and the contaminants adhered to the surface of the earth and sand due to friction between the soil and the like in the washing machine. And introduces water containing sediment and contaminants into a separation tank filled with water and a separation device equipped with a vibrating screen and air supply means, and in the separation tank of the separation device, vibration is applied to the sediment. In addition, sediment and contaminants are separated by blowing air bubbles to settle.

[0007] In this method for purifying contaminated soil, first, soil having a predetermined particle size or more, from which contaminants such as oil are adhered, is easily classified by a sorter. The load of the subsequent steps can be reduced. The sediment having a predetermined particle size or more classified by the sorter can be reused by easily washing with rinsing water since pollutants are easily separated. On the other hand, the sediment that has been classified and removed from the soil having a predetermined particle size is added to water, introduced into a washing machine, and in the washing machine, contaminants adhered to the surface of the earth and sand due to friction between the sand and the like are separated, and the soil is removed. And water containing contaminants are introduced into a separation tank filled with water and a separation apparatus equipped with a vibrating screen and air supply means, and in the separation tank of the separation apparatus, vibration is applied to the sand and air bubbles are blown. The sediment separates the soil and contaminants, so the contaminants adhering to the surface of the sediment can be assured with only a small amount of water without using a cleaning aid such as a surfactant. Can be separated and separated, and the earth and sand can be reused.

The separation apparatus of the present invention used in the method for purifying contaminated soil of the present invention includes a separation tank filled with water into which water containing soil and contaminants is introduced, and a separation tank provided near the bottom of the separation tank. A vibrating screen arranged to vibrate by vibrating means and passing the introduced earth and sand while applying vibration, and a vibrating screen arranged below the vibrating screen and directed toward the sediment on the vibrating screen. It is characterized by comprising air supply means for blowing and transport means for carrying out the settled earth and sand.

[0009] The separation device used for purifying the contaminated soil is as follows:
The vibrating screen and air supply means are used to blow air bubbles while applying vibration to the earth and sand. Therefore, contaminants separated from the earth and sand surface due to friction between the earth and sand in the washing machine are reliably separated from the earth and sand. Then, the settled earth and sand can be carried out by the conveying means.

[0010] In this case, a separating device used for purifying the contaminated soil includes a foam removing blade that removes foam on the water surface by rotating from the separating tank by rotation, and a vacuum device that sucks up contaminants such as oil floating on the water surface. Can be provided.

[0011] Thus, the contaminants separated and separated from the surface of the earth and sand can be surely separated from the earth and sand and can be recovered together with a small amount of water. It can be performed efficiently.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the method for purifying contaminated soil of the present invention and a separation apparatus used for the method will be described below with reference to the drawings.

FIG. 1 and FIGS. 2 to 4 show an embodiment of the method for purifying contaminated soil according to the present invention.

In this method for treating soil, the soil to which contaminants such as oil have adhered is passed through the sorter 1, and the sediment (sand and gravel) B having a predetermined particle size (Nmm) or more, at which the contaminants can be easily separated.
Classify. In this case, the classification can be determined according to the contaminated soil to be purified.
It is desirable to set the particle size in the range of 0 to 50 mm.

The soil B having a predetermined particle size or more classified by the sorter 1 can be reused by easily washing with rinsing water because pollutants are easily separated. The rinse water at this time is
It is sent to a water tank 6 described later and processed.

On the other hand, soil A having a small particle diameter containing a large amount of contaminants is obtained by classifying and removing the soil having a predetermined particle diameter or more.
After being conveyed to the washing machine 3 shown in FIG. 5 by the belt conveyor 2, water is added in the washing machine 3, and mutual polishing is performed by friction between soil and sand, as shown in FIG. Then, the pollutant D on the surface of the soil A is released.

The washing machine 3 includes a rotatable drum 31 and a rotor 32 eccentrically provided in the drum 31 and rotating in the opposite direction to the drum 31.
Grinding and milling are performed by rotating the rotor 1 and the rotor 32 in opposite directions while applying pressure to the earth and sand. As a result, the rubbing force between the soil and sand is applied to the soil A containing the contaminant to perform mutual polishing by friction between the soil and sand, and as shown in FIG. Of the contaminants D
As shown in (d), the sediment A can be finely sized.

Next, the water containing the sediment A and the contaminant D from which the contaminants adhered to the surface are separated is used as a water-separated separation tank 41, a vibrating screen 42, and air supply means as shown in FIGS. Device 4 provided with air blow pipe 43
The sediment A and the contaminant D are separated from the sediment A by applying vibration to the sediment in the separation tank 41 of the separation device 4 and blowing air bubbles to settle the sediment.

As shown in FIG. 6 to FIG.
A separation tank 41 filled with water into which water containing the sediment A and the pollutant D is introduced, and a vibration tank is disposed near the bottom of the separation tank 41 so as to pass the introduced sediment A while applying vibration. A vibrating screen 42, an air blow pipe 43 disposed below the vibrating screen 42 and serving as an air supply means for supplying air bubbles into the separation tank 41, and an air blow pipe 43.
And a belt conveyor 44 as a transporting means for carrying out the settled earth and sand A.

The separation tank 41 is provided with a foam elimination blade 45 for rotating the foam on the water surface by rotation to remove the foam, and a vacuum device 46 for sucking up contaminants D such as oil floating on the water surface, and a vacuum device 46. The contaminant D, which is disposed downstream of the device 46 and floats, is supplied to the belt conveyor 4.
A partition 47 is provided to isolate the partition 47 from the partition 4. The contaminant D sucked up by the vacuum device 46 is sent to the oil separator 5 after passing through the steam separator 46a, where the oil and sewage (contaminants such as oil containing a small amount of water) are separated. Separated and treated as industrial waste. Further, the fine sand settled below the belt conveyor 44 in the separation tank 41 is sucked up by the pump P, and is re-charged into the separation tank 41 together with new earth and sand A.

The vibrating screen 42 is not particularly limited, but is made of, for example, a mesh of about 5 mm. The vibrating screen 42 is formed of a diagonally formed separation tank 41 supported by the vibrating means 42a. It is arranged almost parallel to the bottom.

The air blow pipe 43 converts the air sent from the blower device 43a into fine bubbles,
Pass through 2. The air bubbles from the air blow tube 43
The soil A on the vibrating screen 42 is agitated to enhance the washing effect, and also serves to float contaminants such as oils to the water surface.

The belt conveyor 44 is disposed along the bottom of the separation tank 41, and is provided with a dewatering vibrating means 44a above the water. On the downstream side of the vibration means 44a, a pressurized water pipe 4 for preventing contaminants from being attracted to the conveyed earth and sand A by injecting pressurized water onto the water surface or water.
4b is provided. Further, if necessary, a washing water pipe 44 for washing the conveyed earth and sand A is provided upstream of the vibration means 44a and upstream of the vacuum device 46.
A cleaning water pipe 44d can be provided to assist the suction of the contaminants D such as oil and the like into the vacuum device 46 and the vacuum device 46. The pressure water pipe 44b and the washing water pipe 44d are
In addition to injecting pressurized water, it may be configured to inject pressurized air.

Since the separation device 4 blows air bubbles while applying vibration to the soil A by the vibrating screen 42 and the air blow pipe 43, the cleaning device 3 is used.
In this case, the contaminant D separated from the surface of the soil A due to friction between the soil A is reliably separated from the soil, and the sediment A settled by the belt conveyor 44 can be carried out. As a result, the contaminant D adhering to the surface of the earth and sand A is reliably separated and separated from the earth and sand A with only a small amount of water without using a cleaning aid such as a surfactant. Surface of the contaminant D,
The contaminant D separated from the sediment A can be recovered together with a small amount of water, and can be efficiently separated and recovered by the oil separator 5 described below.

On the other hand, the sediment A settled in the separation tank 41 of the separation device 4 is taken out of the separation device 4 by the belt conveyor 44 and transported to the dewatering sieve 7 provided on the water tank 6. The earth and sand A conveyed to the dewatering sieve 7 is easily washed with rinsing water, if necessary, and then dewatered, so that reusable clean earth and sand A can be obtained.

On the other hand, the drain water from the separation tank 41 is introduced into the water tank 6 together with the rinsing water of the earth and sand B having a predetermined particle size or more classified by the separator 1, and is subjected to a purification treatment by a known treatment method. That is, a precipitation treatment is performed in the water tank 6, and the slurry precipitated at the bottom of the water tank 6 is introduced into the slurry tank 8, and then separated into a dewatered cake and treated water by the dewatering device 9, and the treated water is reacted. It is sent to the tank 10.

The upper water in the water tank 6 is treated together with the treated water from the dehydrator 9 and the treated water from the oil separator 5.
After being sent to the reaction tank 10, it is sequentially processed through the primary reaction tank 11, the secondary reaction tank 12, the tertiary reaction tank 13, the primary flocculation tank 14 and the secondary flocculation tank 15, and then introduced into the precipitation tank 16. . The treated water introduced into the settling tank 16 is transferred to the treated water tank 17 where the upper water is reused as rinsing water, water for water addition, etc., and the drain water is returned to the slurry tank 8 for reprocessing.

As described above, according to the method of purifying contaminated soil according to the present embodiment, first, the sediment B having a predetermined particle size or more is easily separated from the soil to which the contaminants such as oil are attached.
Are classified by the sorter 1, so that the load of the subsequent steps can be reduced. The soil B having a predetermined particle size or more classified by the sorter 1 can be reused by easily washing with rinsing water since pollutants are easily separated.
On the other hand, the sediment A obtained by classifying and removing the sediment B having a predetermined particle size or more is added to the washing machine 3, and the contaminants adhering to the surface of the soil A due to friction between the sand and the like in the washing machine 3. D, and water containing sediment A and pollutant D
The sediment A is introduced into the separation tank 41 provided with water and the separation apparatus 4 provided with the vibrating screen 42 and the air supply means 43. In the separation tank 41 of the separation apparatus 4, the sediment A is vibrated and air bubbles are blown. Since the sediment A separates the sediment A from the contaminant D, the contaminant adhering to the surface of the sediment with only a small amount of water without using a cleaning aid such as a surfactant. Surely leave,
It can be separated and the soil can be reused.

As described above, the method for purifying contaminated soil and the separation apparatus used in the present invention have been described based on the embodiments. However, the present invention is not limited to the configuration described in the above embodiments, For example, a different type of washing machine may be used, and the configuration may be appropriately changed without departing from the gist of the invention.

[0030]

According to the method for purifying contaminated soil of the present invention,
First, since the sediment having a predetermined particle size or more that easily separates the contaminant from the sediment to which the contaminant such as oil is attached is classified by the sorter, the load on subsequent steps can be reduced. . The sediment having a predetermined particle size or more classified by the sorter can be reused by easily washing with rinsing water since pollutants are easily separated. On the other hand, the sediment that has been classified and removed from the soil having a predetermined particle size is added to water, introduced into a washing machine, and in the washing machine, contaminants adhered to the surface of the earth and sand due to friction between the sand and the like are separated, and the soil is removed. And water containing contaminants are introduced into a separation tank filled with water and a separation apparatus equipped with a vibrating screen and air supply means, and in the separation tank of the separation apparatus, vibration is applied to the sand and air bubbles are blown. The sediment separates the soil and contaminants, so the contaminants adhering to the surface of the sediment can be assured with only a small amount of water without using a cleaning aid such as a surfactant. Can be separated and separated, and the earth and sand can be reused. As a result, the cleaning efficiency is improved, so that the load after the cleaning step is reduced by classifying the soil having a predetermined particle size or more in the previous step of the cleaning step, and the cost of purifying the contaminated soil is reduced. can do. Also, after the cleaning step,
A series of treatments can be performed without classifying the earth and sand, so that the treatment steps can be simplified and costs such as equipment costs can be reduced.

According to the separation apparatus of the present invention for purifying contaminated soil, the vibrating screen and the air supply means blow air bubbles while imparting vibrations to the soil. Pollutants separated from the surface of the earth and sand due to friction between them can be reliably separated from the earth and sand, and the settled earth and sand can be carried out by the transporting means. As a result, it is possible to reliably remove and separate contaminants adhering to the surface of the earth and sand by using only a small amount of water without using a cleaning aid such as a surfactant, and to reuse the earth and sand. Become.

Further, the separation apparatus used for purifying the contaminated soil includes a foam elimination blade that removes the foam on the water surface by rotating from the separation tank by rotation, and a vacuum apparatus that sucks up contaminants such as oil floating on the water surface. By providing, the contaminants separated and separated from the surface of the earth and sand can be surely separated from the earth and sand, and can be collected together with a small amount of water.
Recovery can be performed efficiently.

[Brief description of the drawings]

FIG. 1 is a flowchart showing one embodiment of a method for purifying contaminated soil according to the present invention.

FIG. 2 is a flowchart (part 1) of an equipment apparatus showing one embodiment of a method for purifying contaminated soil according to the present invention.

FIG. 3 is a flowchart (part 2) of the equipment showing one embodiment of the method for purifying contaminated soil according to the present invention.

FIG. 4 is a flowchart (No. 3) of the equipment showing one embodiment of the method for purifying contaminated soil according to the present invention.

FIGS. 5A and 5B show a cleaning machine used for purifying contaminated soil according to the present invention, wherein FIG. 5A is a cross-sectional view thereof, FIG. 5B is a cross-sectional view showing the operation thereof, and FIG. FIG. 3D is an explanatory view showing a milling action by the washing machine.

FIG. 6 is a schematic diagram showing a separation device used for purifying contaminated soil according to the present invention.

FIG. 7 is a plan view of the same.

FIG. 8 is a front view of the same.

FIG. 9 is a left side view of the same.

DESCRIPTION OF SYMBOLS 1 Sorting machine 2 Belt conveyor 3 Cleaning machine 31 Drum 32 Rotor 4 Separation device 41 Separation tank 42 Exciting screen 42a Exciting means 43 Air blow tube (air supply means) 43a Blower device 44 Belt conveyor 44a Exciting means 44b Pressure water pipe 44c Wash water pipe 45 Foam elimination blade 46 Vacuum device 47 Partition wall 5 Oil separator 6 Water tank 7 Dewatering sieve 8 Slurry tank 9 Dewatering device 10 Reaction tank 11 Primary reaction tank 12 Secondary reaction tank 13 Tertiary reaction tank 14 Primary coagulation Tank 15 Secondary flocculation tank 16 Sedimentation tank 17 Treated water tank

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[Procedure amendment]

[Submission date] November 8, 2000 (200.11.
8)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

FIG. 3

FIG. 9

FIG. 2

FIG. 4

FIG. 5

FIG. 6

FIG. 7

FIG. 8

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takuo Nakajima 4-55, Kodena-ku, Osaka-shi, Osaka, Japan Konoike-gumi Co., Ltd. (72) Inventor Kawanishi Sequentially, 4-55, Konohana-ku, Osaka, Osaka No. Konoike Gumi Co., Ltd. F term (reference) 4D004 AA41 AB02 CA08 CA13 CA15 CA40 CA50 CB09 CB44 CB45 CB46 CB50 4D051 AA01 AB02 BA09 CA01 CA22 DD01 DD22

Claims (3)

[Claims] 1. A sediment having a predetermined particle size or more, from which a contaminant is easily separated, is classified from a sediment to which a contaminant such as oil is attached by a sorter, and the sediment having the predetermined particle size or more is classified and removed. Water is added to the soil and introduced into the washing machine, where the contaminants attached to the surface of the soil are removed by friction between the sand and the like in the washing machine. The sediment is introduced into a separation device equipped with a vibrating screen and air supply means, and in the separation tank of the separation device, sediment is separated from contaminants by applying vibration to the sediment and blowing bubbles to settle the sediment. Characteristic method of purifying contaminated soil. 2. A separation tank filled with water into which water containing sediment and contaminants is introduced, and disposed near the bottom of the separation tank so as to vibrate by vibrating means. A vibrating screen for passing while applying, an air supply means disposed below the vibrating screen and blowing air bubbles toward the earth and sand on the vibrating screen, and a conveying means for carrying out the settled earth and sand A separation device for purifying contaminated soil, characterized by the following. 3. The apparatus according to claim 2, further comprising a foam removing blade for rotating the foam on the water surface from the separation tank to remove the foam by rotation, and a vacuum device for sucking up contaminants such as oil floating on the water surface. A separation device for use in purifying contaminated soil according to the above.