JPH10309563A - Purifying device of soil and purifying method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a soil purifying device and a purifying method capable of purifying the soil in a portion deeper than a water level of the underground and without generating the residual soil after the purification. SOLUTION: A hollow shaped agitation device 2 is inserted into the soil covered with a shielding member 3 and pressurized hot wind or super-heated steam is discharged from the tip of the agitation device 2 to stir, to accelerate evaporation of a volatile harmful substance in the soil, to make the evaporated volatile harmful substance retain 3 in the shielding member and to recover the harmful substance from the retained volatile harmful substance with a harmful substance recovery device 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soil purification apparatus for removing volatile harmful substances from soil by subjecting the soil contaminated with harmful substances to aeration using warm air or superheated steam, and a purification apparatus therefor. About the method.

[0002]

In recent years, volatile harmful substances such as trichloroethylene, carbon tetrachloride, and tetrachloroethylene have often been used as solvents and cleaning agents in factories and the like, and the volatile harmful substances have permeated the soil to contaminate groundwater. However, volatile harmful substances are diffused around the factory through the groundwater, which has been highlighted as a social environmental pollution problem.

[0003] Therefore, as a method of purifying the soil by removing volatile harmful substances from the soil contaminated with the volatile harmful substances, a perforated extraction well reaching the groundwater level in the contaminated soil is provided. By aspirating the air in a portion shallower than the groundwater level in the extraction well, the volatilization of volatile harmful substances present in the soil around the extraction well is promoted, and volatile harmful substances are removed from the soil through the extraction well. There was a way to remove it.

As disclosed in Japanese Patent Application Laid-Open No. 7-275837, quick lime is mixed with soil contaminated with volatile harmful substances, and volatile harmful substances are volatilized by utilizing a hydration reaction with water in the soil. There was also a method of purifying the soil.

[0005]

However, the above method of sucking volatile harmful substances has a problem that it is difficult to remove volatile harmful substances existing in a portion deeper than the groundwater level. Since the removal of the volatile harmful substances depends on the permeability of the soil around the extraction well, there is a problem that it is impossible to predict how much harmful substances can be removed.

In the method of mixing quicklime with soil, a tangible material such as quicklime is mixed in order to remove volatile harmful substances from the soil, and this mixed residual soil is generated. In this method, the residual soil in the soil undergoes a chemical change with the passage of time, and the strength is developed, which may cause inconvenience depending on the location.

The present invention has been made in view of the above-mentioned problems, and provides a soil purification apparatus and a purification method capable of purifying soil in a portion deeper than a groundwater level and generating no residual soil after purification. Is what you do.

[0008]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a hot air superheated steam generator for generating pressurized hot air or superheated steam, and the hot air or superheated steam generated in soil. A stirrer that discharges and stirs to promote the volatilization of volatile harmful substances in the soil, a shielding member installed on the top of the stirrer for retaining the volatile volatile harmful substances, and a shielding member connected to the shielding member, And a harmful substance recovery device for recovering harmful substances from volatile harmful substances, thereby enabling purification of soil deep underground. Further, in this purification method, a hollow stirrer is inserted into soil covered with a shielding member, and hot air or superheated steam pressurized from the tip of the stirrer is discharged to stir, and the volatility in the soil is reduced. It promotes the volatilization of the harmful substance, causes the volatilized volatile harmful substance to stay in the shielding member, and collects the harmful substance from the staying volatile harmful substance by a harmful substance recovery device.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a soil purification apparatus and a soil purification method according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a conceptual diagram showing a soil purification device according to the present invention, FIG. 2 is a conceptual diagram of a hot air superheated steam generator used in the soil purification device of FIG. 1, and FIG. It is a principal part enlarged view of the stirring apparatus used for the 1 soil purification apparatus.

First, as shown in FIG. 1, a purifying apparatus A used for purifying contaminated soil includes a hot air superheated steam generator 1 for generating hot air or superheated steam, and a hot air superheated steam generator 1. A hollow stirring device 2 for discharging the pressurized hot air or superheated steam generated to the contaminated soil, and a gas containing volatile harmful substances generated from the contaminated soil by the pressurized hot air or superheated steam. Hood 3 which is a shielding member to be retained
And a harmful substance recovery device 4 for recovering harmful substances from the retained gas containing volatile harmful substances.

As shown in FIG. 2, the hot air superheated steam generator 1 has a heater 11, a compressor 12, and a pump 1 inside.
3. A heater 14 and the like are provided, and the air sucked from the air suction pipe 1a is heated by the heater 11 to a temperature higher than the boiling point of the volatile harmful substance to generate hot air.
The pressure is increased to 00 kPa and supplied to the stirring device 2 via the connection pipe 1c. Water pipe 1b
Through the heater 14 and heated by the heater 11 to generate superheated steam at 160 ° C to 200 ° C,
It can also be supplied to the stirring device 2 by the pump 13 via the connection pipe 1c.

As shown in FIG. 1, the stirring device 2 is a stirring rod 20 for discharging hot air or superheated steam sent from the hot air superheated steam generator 1 to the contaminated soil.
And a lower stirring blade 22 for stirring the soil and an upper stirring blade 23 at the lower end of the hollow portion 21. The hollow portion 21 of the stirring rod 20 is a long hollow tube that penetrates the hood 3 described later, and the upper end 21a is connected to the hot air superheated steam generator 1, and the temperature generated by the hot air superheated steam generator 1 is generated. It receives wind or superheated steam, and the lower end 21
b, and discharges high-pressure, high-temperature hot air or superheated steam from the discharge port 21c into the contaminated soil.

As shown in FIG. 3, the lower stirring blade 22 attached to the tip of the stirring rod 20 excavates contaminated soil to a predetermined depth with the lower stirring blade 22 on the tip side, and at a predetermined depth. It can rotate and stir contaminated soil. In addition, the upper stirring blade 23 mounted on the stirring rod 22 is provided with a high-pressure, high-temperature hot air or superheated steam discharged from the discharge port 21c, and the gap K is excavated as it is.
Further ascent is prevented so that high pressure, high temperature hot air or superheated steam permeates downward.

As shown in FIG. 1, a hood 3, which is a shielding member provided above the extraction well, prevents volatile harmful substances volatilized from contaminated soil by hot air or superheated steam from scattering to the outside. In the hood 3, a through hole 3 a of the hollow portion 21 of the agitator 2 is formed in the center of the cylindrical cover, and the volatile harmful substance that has accumulated on the side surface is transferred to the harmful substance recovery device 4. A connection pipe 3b is attached for sending. A drive device 8 is provided on the hood 3, and a drive mechanism such as a motor (not shown) is provided so that the stirring rod 20 penetrating the hood 3 can rotate and move up and down.

The harmful substance recovery device 4 connected to the hood 3 by a connection pipe 3b includes a separation device 5, an exhaust device 6, and a recovery tank 7, and separates and purifies harmful substances from volatile harmful substances. The harmful substances are stored in the recovery tank 7, and the purified air is exhausted into the air. Separation device 5
Is an exchanger 5a equipped with an adsorbent for harmful substances such as activated carbon.
And an air pump 5b for sending air from which harmful substances have been removed to an exhaust device 6, and a pump 5c for sending harmful substances accumulated in the separation device 5 to a recovery tank 7. The exhaust device 6 exhausts air purified by separating harmful substances by the separation device 5 into the air. The exhaust device 6 includes various filters and sensors, and monitors whether the exhausted air contains harmful substances. doing. The collection tank 7 stores the harmful substances that have become liquid, and is processed separately when a certain amount of the harmful substances is collected.

A method for purifying soil in the purification device A thus configured will be described with reference to FIG. First, a stirrer 2 is installed by a tower or a crane, etc., at a site to be purified of soil contaminated with volatile harmful substances, and excavation is performed to a predetermined depth. Further, a hood 3 is installed by penetrating the stirrer 2 on the ground surface above the stirrer 2.
And the harmful substance recovery device 4 are connected by a connection pipe 3b, and further, the stirring device 2 and the hot air superheated steam generator 1 are connected by a connection pipe 1c.

Next, in the hot air superheated steam generator 1, if the volatile harmful substances can be aerated only by the warm air due to the soil conditions, the air sucked from the air suction pipe 1a is set to a temperature higher than the boiling point of the volatile harmful substances. The mixture is heated by the heater 11, and is further pressurized to 200 to 400 kPa by the compressor 12 and supplied to the stirring device 2. In addition, when it is necessary to dry the soil due to soil conditions, the water supply pipe 1
The superheated steam having a temperature of 160 ° C. to 200 ° C. is generated through the heater 14 in a state where the water supplied from b is pressurized, and supplied to the stirring device 2 by the pump 13.

Next, in the stirring device 2, the hot air or the superheated steam supplied from the hot air superheated steam generator 1 is discharged into the contaminated soil in a state where it is pressurized from the discharge port 21 c, and furthermore, by the stirring rod 20. Stirring the contaminated soil,
The hot air or superheated steam penetrates the agitated soil and raises the temperature of the agitated contaminated soil above the boiling point of the volatile harmful substances. Then, the volatile harmful substances contained in the contaminated soil evaporate and evaporate, and the gasified volatile harmful substances rise in the excavated space K, and the hood 3
Stays inside. Therefore, the volatile harmful substances are aerated in the agitated soil, and the soil is purified. Further, the hot air or the superheated steam is supplied to the discharge port 21 in a pressurized state.
c, and penetrates downward by the upper stirring blade 23, so that it can penetrate not only to the excavated groundwater level but also to the soil deeper than the groundwater and purify volatile harmful substances in this soil. it can.

The volatile harmful substances remaining in the hood 3 are sent from the hood 3 to the harmful substance recovery device 4 via the connection pipe 3b, and are separated into harmful substances and air by the separation device 5 of the harmful substance recovery device 4. Separated. Then, the separated air is sent to the exhaust device 6 by the air pump 5b, purified to a concentration equal to or lower than a reference value of environmental pollution, and discharged into the air. The harmful substances separated by the separation device 5 are sent to the collection tank 7 by the pump 5c and stored.

[0020]

As described above, the present invention provides a hot air superheated steam generator for generating pressurized hot air or superheated steam, and discharges and stirs the hot air or superheated steam into the soil to produce the soil. A stirrer rod for promoting the volatilization of volatile harmful substances therein, a hood installed on the stirrer rod to retain the volatile volatile harmful substances, and a harmful substance from the volatile harmful substances connected to the hood. And a hazardous substance recovery device to be recovered, and a stirrer is inserted into the soil,
Since the soil can be purified by aeration of volatile harmful substances while stirring, the soil to be purified is reliably purified without depending on the physical state of the soil.

The hot air or superheated steam discharged into the soil is stirred by applying pressure to the soil.
It can also purify soil deeper than groundwater. Further, the hot air or the superheated steam containing the volatile harmful substance is collected by the harmful substance recovery device and does not remain in the soil, so that the generated residual soil after purification can be suppressed. Furthermore, since the soil after purification does not utilize a hydration reaction or the like, it does not chemically change over time, and problems such as the development of strength are resolved.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a soil purification device according to the present invention.

FIG. 2 is a conceptual diagram of a hot air superheated steam generator used in the soil purification device of FIG.

FIG. 3 is an enlarged view of a main part of a stirring device used in the soil purification device of FIG. 1;

[Explanation of symbols]

 A Purifier 1 Hot air superheated steam generator 2 Stirrer 3 Hood 4 Hazardous substance recovery device 5 Separation device 6 Exhaust device 7 Recovery tank 8 Drive device 11 Heater 12 Compressor 13 Pump 14 Heater 20 Stirring rod 21 Hollow portion 22 Lower stage stirring Wing 23 Upper stage stirring blade

Claims (2)

[Claims] 1. A hot air superheated steam generator for generating pressurized hot air or superheated steam, and discharges and agitates the hot air or superheated steam into soil to promote volatilization of volatile harmful substances in the soil. A stirrer, a shielding member installed above the stirrer to retain the volatile volatile harmful substances, and a harmful substance recovery device connected to the shielding member and collecting harmful substances from the volatile harmful substances, A soil purification device comprising: 2. Inserting a hollow stirrer into the soil covered with a shielding member, and discharging the hot air or superheated steam from the tip of the stirrer to stir, thereby causing volatile harm in the soil. A soil purification method comprising: promoting volatilization of a substance; retaining the volatilized volatile harmful substance in the shielding member; and collecting a harmful substance from the retained volatile harmful substance by a harmful substance recovery device. .