JP4646047B2 - Method for purifying contaminated soil and separation apparatus used therefor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for purifying contaminated soil, which can improve cleaning efficiency and reduce the purification cost of contaminated soil, and a separation apparatus used therefor.
[0002]
[Prior art]
In recent years, it has become clear that various manufacturing factories and the soil in the former site are contaminated with pollutants such as oil, which has become a social problem.
In addition, crude oil and fuel oil spilled due to maritime accidents such as tankers, beach soil contaminated with waste oil illegally dumped from ships, and soil (including excavated soil) to which crude oil from the crude oil mining site is attached. There was no appropriate purification method in relation to costs.
[0003]
[Problems to be solved by the invention]
Against this background, it is desirable to establish a technology that makes it possible to reuse land by removing pollutants from contaminated soil, protects the natural environment, and reuses soil from which pollutants have been removed. Yes.
[0004]
By the way, there is a soil washing method as one of the purification methods for contaminated soil containing oil, but the conventionally proposed soil washing method is used when the concentration of pollutants is high and the oil is heavy oil or tar. However, in order to remove contaminants adhering to the surface of the earth and sand, it was necessary to use a large amount of water, go through a plurality of washing steps, and use a cleaning aid such as a surfactant.
Therefore, in such a soil cleaning method, in addition to equipment costs, water treatment costs, costs for cleaning aids such as surfactants increase, and the unit cost of treatment increases, resulting in poor practicality. there were.
[0005]
In view of the problems of the conventional contaminated soil purification method, in particular, the soil cleaning method, the present invention improves the cleaning efficiency and reduces the contaminated soil purification cost. And it aims at providing the separation apparatus used for it.
[0006]
[Means for Solving the Problems]
To achieve the above object, method of purifying contaminated soil of the present invention, the sediment contaminants adhered containing oil was classified by pre Me sorter, adding water to the soil removal of the sediment on the particle diameter or more of Jo Tokoro Te, is introduced into the washing machine, the washing machine is detached more contaminants adhering to the surface of the sediment friction sediment together, sand and water containing contaminants, the separation vessel and vibrating screens and air filled with water Introduced into a separation device equipped with a supply means, in the separation tank of the separation device, air bubbles are blown from the air blow pipe of the air supply means arranged under the vibration screen, the earth and sand are stirred, washed, and settled , the Rukoto to float contaminants on the surface of the water, and separating the sediment and contaminants.
[0007]
Purification method of this contaminated soil, first, since the sediment contaminants including oil has adhered are to be classified by pre Me sorter, it is possible to reduce the load on the subsequent steps. And since the earth and sand with the predetermined particle diameter or more classified by the sorter are easily separated from contaminants, they can be reused by simply washing with rinse water.
Meanwhile, the sediment classification to remove sediment on the predetermined particle diameter or less, hydrolysis to, and introduced into the washing machine, to disengage more contaminants adhering to the surface of the sediment friction sediment between the washer, sand In addition, water containing contaminants is introduced into a separation tank equipped with water and a separation apparatus equipped with a vibration screen and air supply means, and in the separation tank of the separation apparatus, vibration is applied to the earth and sand on the vibration screen. from air blow pipe of the air supply means is disposed below the vibrating screen while blowing bubbles stirring the sediment by washing, precipitated by Rukoto floated contaminants on the surface of the water, separate the sediment and contaminants Therefore, without using a cleaning aid such as a surfactant, the contaminants attached to the surface of the earth and sand can be surely removed and separated with only a small amount of water, and the earth and sand can be reused. What can It made.
[0008]
Moreover, the separation device 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 earth and sand and contaminants is introduced, and a vibrating means near the bottom of the separation tank. A vibrating screen that is arranged to vibrate and passes through the introduced earth and sand while applying vibration, and air bubbles from the air blow pipe arranged under the vibrating screen toward the earth and sand on the vibrating screen the sprayed washing stirred sediment, allowed to settle, and the air supply means Ru is floated contaminants on the water surface, characterized by comprising a conveying means for carrying out the precipitated sediment.
[0009]
Separation apparatus for use in purifying the contaminated soil by vibration screen and air supply means, while applying vibration to the sediment, since the blown air bubbles, from the more sediment surface of the friction sediment between the washer The detached pollutant can be reliably separated from the earth and sand, and the settled earth and sand can be carried out by the conveying means.
[0010]
In this case, the separation device used for the purification of the contaminated soil includes a foam removal blade that removes foam on the water surface by rotating it from the separation tank, and a vacuum device that sucks up the contaminants including oil floating on the water surface. be able to.
[0011]
As a result, the contaminants separated and separated from the surface of the earth and sand can be reliably separated from the earth and sand and recovered together with a small amount of water, and the separation and recovery of the contaminants in an oil separator or the like in the subsequent process is efficiently performed. be able to.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a method for purifying contaminated soil according to the present invention and a separation apparatus used therefor will be described below with reference to the drawings.
[0013]
1 and 2 to 4 show an embodiment of the method for purifying contaminated soil of the present invention.
[0014]
In this earth and sand processing method, earth and sand (sand gravel) B having a predetermined particle size (Nmm) or more that is easy to separate the contaminants is classified by applying the earth and sand to which the contaminants such as oils adhere to the sorter 1.
In this case, classification can be determined according to the contaminated soil to be purified, but it is desirable to set the particle size (Nmm) to a particle size in the range of 20 to 50 mm.
[0015]
And since the earth and sand B with the predetermined particle diameter or more classified by the sorter 1 is easily separated from contaminants, it can be reused by simply washing with rinse water.
In addition, the rinse water at this time is sent to the water tank 6 mentioned later, and is processed.
[0016]
On the other hand, the soil A having a small particle size and containing a large amount of contaminants, which has been removed by classifying the soil having a predetermined particle size or more, is conveyed by the belt conveyor 2 to the washer 3 shown in FIG. As shown in FIG. 5 (c), the contaminant D on the surface of the earth and sand A is released by being hydrolyzed in the machine 3 and performing mutual polishing by friction between the earth and sand.
[0017]
The washing machine 3 includes a drum 31 that is rotatably provided, and a rotor 32 that is eccentrically provided in the drum 31 and rotates in a direction opposite to the drum 31. The drum 31 and the rotor 32 are pressed against the earth and sand. Grinding and rubbing are performed by rotating them in reverse directions while adding.
As a result, the rubbing force between the earth and sand is applied to the earth and sand A containing the pollutant, and mutual polishing is performed by friction between the earth and sand. As shown in FIG. The soil D can be finely sized as shown in FIG.
[0018]
Next, the water containing the soil A and the contaminant D from which the contaminants adhered to the surface are separated is separated from the separation tank 41 filled with water shown in FIGS. 6 to 9, the vibration screen 42, and an air blow pipe as an air supply means. Introducing into the separation device 4 provided with 43, in the separation tank 41 of this separation device 4, the earth and sand A and the pollutant D are separated by imparting vibrations to the earth and sand and blowing air bubbles.
[0019]
As shown in FIGS. 6 to 9, the separation device 4 is disposed so as to vibrate near the bottom of the separation tank 41 and a separation tank 41 filled with water into which water containing soil A and contaminants D is introduced. A vibrating screen 42 that allows the introduced earth and sand A to pass while applying vibration, and an air blow pipe 43 that is disposed under the vibrating screen 42 and that supplies air bubbles into the separation tank 41. A belt conveyor 44 is provided below the air blow pipe 43 and serves as a conveying means for carrying out the sediment A and sediment.
[0020]
The separation tank 41 is provided with a foam removal blade 45 that causes the foam on the water surface to flow over by rotation, and a vacuum device 46 that sucks up the contaminants D such as oil floating on the water surface, and a vacuum device 46. A partition wall 47 that is disposed on the downstream side and isolates the floating contaminant D from the belt conveyor 44 is provided.
The pollutant D sucked up by the vacuum device 46 passes through the steam separator 46a and is then sent to the oil separator 5, where oil and sewage (pollutants such as oil containing a small amount of water) are collected. Separated and treated as industrial waste.
Further, the fine sand that has settled below the belt conveyor 44 in the separation tank 41 is sucked up by the pump P and re-introduced into the separation tank 41 together with new earth and sand A.
[0021]
The vibration screen 42 is not particularly limited. For example, the vibration screen 42 is made of a mesh of about 5 mm and is substantially supported by the bottom of the separation tank 41 formed obliquely while being supported by the vibration means 42a. They are arranged in parallel.
[0022]
The air blow pipe 43 makes the air sent from the blower device 43a into fine bubbles and passes it through the vibration screen 42.
The air bubbles from the air blow pipe 43 agitate the earth and sand A on the vibration screen 42 to enhance the cleaning effect, and also play a role of causing contaminants such as oil to rise to the water surface.
[0023]
The belt conveyor 44 is disposed along the bottom of the separation tank 41, and a vibration means 44a for dehydration is provided on the water.
On the downstream side of the vibration means 44a, there is provided a pressure water pipe 44b for preventing the contaminants from being drawn into the earth and sand A carried out by injecting pressurized water into the water surface and water.
Furthermore, if necessary, on the upstream side of the vibration means 44a and the upstream side of the vacuum device 46, a contaminant D such as oil to the cleaning water pipe 44c and the vacuum device 46 for cleaning the sand and sand A carried out. A cleaning water pipe 44d can be provided to help suck up the water.
The pressure water pipe 44b and the washing water pipe 44d can be configured to inject pressurized air in addition to injecting pressurized water.
[0024]
Since this separating device 4 blows bubbles while applying vibration to the earth and sand A by the vibration screen 42 and the air blow pipe 43, the surface of the earth and sand A is caused by friction between the earth and sand A in the washing machine 3. The detached contaminant D can be reliably separated from the earth and sand, and the earth and sand 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 can be reliably separated from the earth and sand A with only a small amount of water without using a cleaning aid such as a surfactant, and the oil content etc. by bubbles The pollutant D separated from the earth and sand A can be recovered together with a small amount of water, and can be efficiently separated and recovered by the oil separator 5 described later.
[0025]
On the other hand, the earth and sand A settled in the separation tank 41 of the separation apparatus 4 is taken out from the separation apparatus 4 by the belt conveyor 44 and transferred to the dewatering sieve 7 disposed on the water tank 6.
The earth and sand A transported to the dewatering sieve 7 can be made clean earth and sand A which can be reused by being dehydrated after being simply washed with rinse water if necessary.
[0026]
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 sorting machine 1 and purified by a known processing method.
That is, in the water tank 6, a precipitation process is performed, and the slurry precipitated at the bottom of the water tank 6 is introduced into the slurry tank 8, and then separated into a dehydrated cake and treated water by a dehydrator 9. It is sent to the tank 10.
[0027]
Moreover, after the upper water of the water tank 6 is sent to the reaction tank 10 together with the treated water from the dehydrator 9 and the treated water from the oil separator 5, the primary reaction tank 11, the secondary reaction tank 12, and the tertiary reaction tank 13. After being processed through the primary flocculation tank 14 and the secondary flocculation tank 15 in this order, they are 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 rinse water, water for hydration, etc., and the drain water is returned to the slurry tank 8 for reprocessing.
[0028]
As described above, according to the method for purifying contaminated soil of the present embodiment, first, the sorter 1 classifies the soil B having a predetermined particle size or more from which the contaminant is easily separated from the soil and the like to which the contaminant such as oil is attached. As a result, the subsequent process load can be reduced. And since the earth and sand B with the predetermined particle diameter or more classified by the sorter 1 is easily separated from contaminants, it can be reused by simply washing with rinse water.
On the other hand, the earth and sand A obtained by classifying and removing the earth and sand B having a predetermined particle size or more is hydrolyzed and introduced into the washing machine 3, and the contaminants adhered to the surface of the earth and sand A due to friction between the earth and sand in the washing machine 3. D is separated, and water containing earth and sand A and pollutant D is introduced into a separation tank 41 filled with water and a separation apparatus 4 having a vibration screen 42 and an air supply means 43, and the separation tank of this separation apparatus 4 In 41, vibration is applied to the earth and sand A and air bubbles are blown and settled to separate the earth and sand A and the pollutant D, so that a cleaning aid such as a surfactant is not used. The pollutant adhering to the surface of the earth and sand can be surely removed and separated with only a small amount of water, and the earth and sand can be reused.
[0029]
As mentioned above, although the purification method of the contaminated soil of this invention and the separation apparatus used for it were demonstrated based on the Example, this invention is not limited to the structure described in the said Example, A different form is used for a washing machine. The configuration can be changed as appropriate without departing from the spirit of the cleaning machine.
[0030]
【The invention's effect】
According to the purification method of the contaminated soil of the present invention, firstly, since the sediment contaminants including oil has adhered are to be classified by pre Me sorter, it is possible to reduce the load on the subsequent steps. And since the earth and sand with the predetermined particle diameter or more classified by the sorter are easily separated from contaminants, they can be reused by simply washing with rinse water.
Meanwhile, the sediment classification to remove sediment on the predetermined particle diameter or less, hydrolysis to, and introduced into the washing machine, to disengage more contaminants adhering to the surface of the sediment friction sediment between the washer, sand In addition, water containing contaminants is introduced into a separation tank equipped with water and a separation apparatus equipped with a vibration screen and air supply means, and in the separation tank of the separation apparatus, vibration is applied to the earth and sand on the vibration screen. from air blow pipe of the air supply means is disposed below the vibrating screen while blowing bubbles stirring the sediment by washing, precipitated by Rukoto floated contaminants on the surface of the water, separate the sediment and contaminants Therefore, without using a cleaning aid such as a surfactant, the contaminants attached to the surface of the earth and sand can be surely removed and separated with only a small amount of water, and the earth and sand can be reused. What can It made.
As a result, the cleaning efficiency is improved, and the soil after the cleaning process is classified in the previous process of the cleaning process so that the load after the cleaning process is reduced. can do.
In addition, after the cleaning step, a series of treatments can be performed without classifying the earth and sand, the treatment step can be simplified, and costs such as equipment costs can be reduced.
[0031]
Further, according to the separation device used for the purification of contaminated soil of the present invention, bubbles are blown while applying vibration to the earth and sand by the vibration screen and the air supply means. contaminants more detached from the surface of the earth and sand, and is reliably separated from the sand, it is possible to carry the soil of sediment by the conveying means.
As a result, it is possible to reliably remove and separate the contaminants adhering to the surface of the earth and sand with a small amount of water without using a cleaning agent such as a surfactant and to reuse the earth and sand. Become.
[0032]
In addition, the separation device used for the purification of contaminated soil is provided with a foam removal blade that removes foam on the water surface by rotating it from the separation tank and a vacuum device that sucks up contaminants including oil floating on the water surface. The pollutants separated from and separated from the surface of the earth and sand can be reliably separated from the earth and sand and collected with a small amount of water. it can.
[Brief description of the drawings]
FIG. 1 is a flowchart showing an embodiment of a method for purifying contaminated soil according to the present invention.
FIG. 2 is a flowchart (No. 1) of the equipment apparatus showing an embodiment of the method for purifying contaminated soil of the present invention.
FIG. 3 is a flowchart (No. 2) of the equipment apparatus showing an embodiment of the method for purifying contaminated soil according to the present invention.
FIG. 4 is a flow chart (No. 3) of the equipment apparatus showing an embodiment of the method for purifying contaminated soil according to the present invention.
FIG. 5 shows a washing machine used for the purification of contaminated soil of the present invention, (a) is a sectional view thereof, (b) is a sectional view showing its operation, and (c) is an explanation showing a grinding action by the washing machine. FIG. 4D is an explanatory view showing the grinding action by the washing machine.
FIG. 6 is a schematic view showing a separation device used for purification of 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.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Sorting machine 2 Belt conveyor 3 Washing machine 31 Drum 32 Rotor 4 Separation device 41 Separation tank 42 Excitation screen 42a Excitation means 43 Air blow pipe (air supply means)
43a Blower device 44 Belt conveyor 44a Excitation means 44b Pressure water piping 44c Wash water piping 45 Foam removal blade 46 Vacuum device 47 Partition wall 5 Oil separator 6 Water tank 7 Dehydration sieve 8 Slurry tank 9 Dehydration apparatus 10 Reaction tank 11 Primary reaction tank 12 2 Next reaction tank 13 Tertiary reaction tank 14 Primary agglomeration tank 15 Secondary agglomeration tank 16 Precipitation tank 17 Treated water tank

Claims (3)

The sediment contaminants adhered containing oil was classified by pre Me sorter, add water to the soil removal of the sediment on the particle diameter or more of Jo Tokoro, it is introduced into the washing machine, and more friction sediment between the washer Contaminants adhering to the surface of the earth and sand are released, and water containing the earth and sand and the contaminants is introduced into a separation tank equipped with water and a separation apparatus equipped with a vibrating screen and air supply means, and the separation tank of the separation apparatus In the inside, the soil on the vibrating screen is vibrated and air bubbles are blown from the air blow pipe of the air supply means arranged under the vibrating screen to stir and wash the sediment and settle it, so that the pollutants are put on the water surface. the Rukoto is floated, method of purifying contaminated soil and separating the sediment and contaminants. A separation tank filled with water to which water containing earth and sand and contaminants is introduced, and arranged to vibrate near the bottom of the separation tank by a vibrating means, and pass through the introduced earth and sand while applying vibration. From the vibration screen and the air blow pipe arranged under the vibration screen, air bubbles are blown toward the earth and sand on the vibration screen to stir and wash the earth and sand, causing contaminants to float on the water surface. The separation apparatus used for the purification of contaminated soil, characterized by comprising an air supply means and a conveying means for carrying out sediment. The contaminated soil according to claim 2 , further comprising: a foam removing blade for removing foam on the water surface by rotating it from the separation tank; and a vacuum device for sucking up contaminants including oil floating on the water surface. Separation device used for purification.

Images