JP2001334290A - Method for cleaning sludge soil, slurry or the like - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for cleaning sludge soil, a slurry or the like, capable of desorbing hydrophobic organic matter from a solid phase at the normal temperature under atomospheric pressure by reduced energy. SOLUTION: A surfactant and a spherical resin (a) are added to the substance 2 to be treated stored in a reaction tank 1 and the spherical resin (a) floating in the vicinity of the surface of the water in the tank is circulated to the bottom part of the tank through a circulating system 6 and the substance 2 to be treated is irradiated with ultrasonic waves exerting vibrtation and extraction action on the solid phase from an ultrasonic transmitter 9 while the spherical resin (a) is circulated within the tank and hydrophobic organic matter is transferred from the solid phase to a liquid phase by the vibrtation and extraction action to be desorbed from the solid phase and the re-adsorption of the hydrophobic organic matter by the solid phase is prevented by the bonding of the surfactant with the hydrophobic organic matter and the desorbed hydrophobic organic matter is adsorbed by the spherical resin (a).

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, slurry, etc., and relates to a harmful hydrophobic organic substance contained in leachate, contaminated soil, slurry, etc. at a final disposal site for general waste and industrial waste. The present invention relates to a technology for attaching and detaching.

[0002]

2. Description of the Related Art Conventionally, hydrophobic harmful organic substances, such as dioxins, PCBs, and aromatic hydrocarbons, contained in soil and slurry have been very strongly adsorbed on solid particles, and are generally treated. Is very difficult. bioremediati
In a biological treatment method in which organic substances are digested by microorganisms such as on, in many cases, only organic substances contained in an aqueous phase can be treated. In addition, for highly volatile substances, it is possible to separate them from the solid phase by thermal desorption, but it is not possible to deal with substances with a high boiling point, and it is necessary to deal with very high processing costs such as incineration. Was.

For example, dioxins in a solid substance are
There are a melting treatment method in which the melting is performed under a high temperature condition of 200 degrees or more, and a supercritical treatment method in which the treatment is performed under a high temperature and high pressure condition of 370 degrees or more and 22 MPa or more. Alternatively, there is an alkali-catalyzed decomposition method in which a hydrogen donor, an alkali, and a solvent are added to an object to be treated, and then heat treatment is performed at about 350 ° C. in a nitrogen atmosphere.

[0004]

However, soil contaminated with hydrophobic organic matter is difficult to purify because the contaminants are strongly adsorbed on the solid phase, and even if bioremediation or other treatments are performed, the soil is not contaminated. There was a limit such that the contaminant concentration in the sample no longer changed. Further, there is only a method that requires a high treatment cost such as the above-described incineration of soil to perform purification, which is not practical.

The present invention solves the above-mentioned problems, and provides a method for purifying contaminated soil, slurry, and the like which can desorb a hydrophobic organic substance from a solid phase under normal temperature and normal pressure with little energy. The purpose is to:

[0006]

In order to solve the above-mentioned problems, a method for purifying contaminated soil and slurry according to the present invention is characterized in that a solid-liquid mixed phase object to be treated stored in a reaction tank has an adsorption capacity for hydrophobic organic substances. Is added, and the spherical resin floating near the water surface in the tank is circulated to the bottom of the tank to circulate the spherical resin in the tank, and from the ultrasonic transmitter disposed in the tank to the object to be treated. The solid phase is irradiated with ultrasonic waves that exerts vibration extraction action, the hydrophobic organic substance is transferred from the solid phase to the liquid phase by the vibration extraction action and desorbed, and the hydrophobic property to the solid phase is bonded by the combination of the surfactant and the hydrophobic organic substance. This prevents the re-adsorption of organic substances and adsorbs the desorbed hydrophobic organic substances to the spherical resin.

[0007] With the above structure, hydrophobic organic substances such as dioxins contained in the object to be treated are adsorbed on the surface layer of the solid phase soil particles, adhere to the pores in the fine gaps of the developing particles, or are contained in the soil particles. It exists in a complex entanglement with the organic matter contained.

The hydrophobic organic matter adsorbed on the surface layer of the soil particles is desorbed from the soil so as to maintain an equilibrium state when in contact with the liquid phase. Therefore, the hydrophobic organic substance in the liquid phase is adsorbed by the spherical resin and the concentration of the hydrophobic organic substance in the liquid phase is reduced,
Hydrophobic organic substances are desorbed from the soil so as to maintain the equilibrium, the concentration of contaminants in the soil is reduced, and purification of the object to be treated proceeds. By flowing the spherical resin in the tank, the frequency of contact with the hydrophobic organic substance is increased, and the adsorption efficiency is improved.

[0009] However, the particles adhere to the pores of the fine particles in the process,
Alternatively, the hydrophobic organic matter present in a complex entanglement with the organic matter contained in the soil particles is very strongly adsorbed to the soil particles and exists in a form that hardly migrates into the liquid phase.

[0010] For this purpose, an ultrasonic wave is applied to the solid phase of the object to be treated, and the vibrational energy is used to change the hydrophobic organic substance into a form that can easily move to the liquid phase, thereby causing the hydrophobic organic substance to move from the solid phase to the liquid phase. The hydrophobic organic substance extracted by the vibration extraction action is easily re-adsorbed to the solid phase again, but the surfactant is bonded to the hydrophobic organic substance, thereby preventing the hydrophobic organic substance from being re-adsorbed to the solid phase, and In the liquid phase. The hydrophobic organic substance in the liquid phase is adsorbed by the spherical resin, the concentration of the hydrophobic organic substance in the liquid phase is reduced, the desorption of the hydrophobic organic substance from the soil is promoted, and the object to be treated is purified.

After the purification of the slurry is completed, the spherical particles are taken out of the tank together with the overflow water. Since the spherical resin floats on water, it can be easily collected. Water may be introduced into the reaction tank to increase the recovery efficiency. The removed spherical resin is washed with a solvent such as toluene, regenerated and reused. The hydrophobic organic substance dissolved in the solvent is separately treated. The treated slurry is pulled out from the bottom and subjected to a treatment such as dehydration.

The ultrasonic wave exerting the vibration extracting action depends on the physical properties of the object to be treated, for example, the type and composition of the hydrophobic organic substance, the properties of sludge and soil, or the shape of the reaction tank, and is determined in advance as an empirical rule.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, an object 2 to be treated stored in a reaction tank 1 is leachate from a landfill at a final disposal site for industrial waste, contaminated soil, slurry, and the like, such as dioxins, PCBs, and aromatic hydrocarbons. Contains hydrophobic organics.

A reaction tank 1 has a supply system 3 for supplying a solid-liquid mixed-phase object 2 to be treated, a drug supply system 4 for supplying a surfactant, and a spherical resin (XAD2) having an adsorbing ability for hydrophobic organic substances. a circulating system 6 is connected to the tank top and the tank bottom, and a discharge system 7 is provided for branching out of the circulating system 6 to take out the processing slurry. An overflow valve 8 is provided above the circulation system 6. The spherical resin (XAD2) is a synthetic adsorbent having a huge network structure, and is a hard, insoluble, porous polymer spherical resin. The physical properties are shown in Table 1.

[0015]

[Table 1] An ultrasonic transmitter 9 (horn) is provided inside the reaction tank 1, and the ultrasonic transmitter 9 is connected to an ultrasonic oscillator 11 through a waveguide 10. The ultrasonic oscillator 11 oscillates ultrasonic vibration which exerts a vibration extracting action on the solid phase of the processing object 2. The ultrasonic transmitter 9 may use a vibrator made of ceramic or the like that oscillates upon receiving a voltage.

The frequency of the ultrasonic wave transmitted from the ultrasonic transmitter 9, that is, the frequency of the ultrasonic wave exerting the vibration extracting action, varies depending on the physical properties of the object 2 to be treated, for example, the type and composition of the hydrophobic organic substance, and the properties of the sludge and the soil. Alternatively, since it depends on the shape of the reaction tank 1, it is determined in advance as an empirical rule.

The operation of the above configuration will be described below. The processing object 2 is supplied from the supply system 3 to the reaction tank 1, and a predetermined amount of the processing object 2 is stored in the reaction tank 1. A predetermined amount of a surfactant, for example, LAS (sodium alkylbenzene sulfonate) is added from the drug supply system 4 so as to maintain the CMC concentration (critical micelle concentration) or higher, and an appropriate amount of spherical resin is added from the adsorbent supply system 5. Input a. The spherical resin a floating near the water surface in the tank is circulated together with the processing object 2 to the bottom of the tank through the circulation system 6, and the processing object 2 and the spherical resin a are circulated and flow in the tank.

Hydrophobic organic substances such as dioxins contained in the processing object 2 are adsorbed on the surface layer of the solid phase soil particles, adhere to the pores in the fine gaps of the developing particles, or are separated from the organic substances contained in the soil particles. It exists in a complex entanglement.

The hydrophobic organic matter adsorbed on the surface layer of the soil particles is desorbed from the soil so as to maintain an equilibrium state when in contact with the liquid phase. For this reason, the hydrophobic organic substance in the liquid phase is adsorbed by the spherical resin a, and the hydrophobic organic substance is desorbed from the soil so as to maintain an equilibrium by reducing the concentration of the hydrophobic organic substance in the liquid phase,
The concentration of the contaminants in the soil decreases, and the purification of the treatment target 2 proceeds. At this time, since the spherical resin a flows in the tank, the frequency of contact with the hydrophobic organic substance increases, and the adsorption efficiency improves.

However, the particles adhere to the pores of the fine particles on the way,
Alternatively, it is difficult to desorb a hydrophobic organic substance existing in a complex entanglement with an organic substance contained in soil particles due to its low solubility only by contacting with a liquid phase.

For this reason, the ultrasonic wave oscillated by the ultrasonic oscillator 11 is irradiated through the waveguide 10 from the ultrasonic wave transmitter 9 onto the object 2 to be processed, and the vibration energy transfers the hydrophobic organic substance from the solid phase to the liquid phase. Let it. The hydrophobic organic substance extracted by the vibration extraction action is easily re-adsorbed to the solid phase again, but the surfactant is bonded to the hydrophobic organic substance, thereby preventing the hydrophobic organic substance from being re-adsorbed to the solid phase, and In the liquid phase. On the other hand, the hydrophobic organic substance transferred to the liquid phase is adsorbed by the spherical resin a, the concentration of the hydrophobic organic substance in the liquid phase is reduced, the desorption of the hydrophobic organic substance from the soil is promoted, and the treatment object 2 is purified.

The spherical resin a is taken out of the tank together with overflow water by opening the valve 8. Since the spherical resin floats on water, it can be easily collected. Water may be introduced into the reaction tank to increase the recovery efficiency. The extracted spherical resin is used for extracting and washing hydrophobic organic substances with a solvent such as toluene, and then reusing it.

Hereinafter, a verification test of the above configuration will be described. FIG. 2 is a conceptual diagram of a two-phase model of an aqueous phase and a soil. The contaminants adsorbed on the soil include those that are adsorbed on the soil with relatively weak force and move to the aqueous phase quickly, and those that are strongly adsorbed and hardly move into water. The ratio of the weak adsorbate is indicated by F, and the ratio of the strong adsorbate is indicated by 1-F. The larger the F, the easier the soil purification.

[0024]

(Equation 1) This two-phase model equation is a model equation that indicates how much (Sx) the initial contaminant amount S ₀ in the soil will be after x hours. FIG. 3 is a graph of the above model equation.
The larger the ratio F of the weak adsorbate, the more contaminants fall, so that the final (Sx) becomes smaller, and the larger the constant k1 of fast desorption, the faster the contaminants fall, so that the slope of the curve becomes steeper.

FIG. 4 shows the results of a two-phase model in which a contaminated soil was inverted and stirred in water to wash away contaminants. Naphthalene was 68%, phenanthrene was 46%, and pyrene was 42%, and water was earlier. Has transitioned to

FIG. 5 shows the results of a two-phase model in which the same contaminated soil was subjected to ultrasonic treatment in the presence of a surfactant and then inverted and stirred. Naphthalene was 93%, phenanthrene was 94%, and pyrene was 90%. % Migrated into the water early, indicating that the purification efficiency has definitely increased.

FIG. 6 shows the ratio F of the weakly adsorbed substance after the treatment shown in FIG. 5, and it is effective to carry out ultrasonic treatment in the presence of a surfactant for other substances. I can tell you something.

[0028]

As described above, according to the present invention, a hydrophobic organic substance is desorbed from a processing object by adding a spherical resin and a surfactant to the processing object and irradiating with ultrasonic waves. The desorbed hydrophobic organic substance is adsorbed by the spherical resin while remaining in a liquid phase with a surfactant, and the hydrophobic organic substance can be separated from the object to be treated and purified. Therefore, hydrophobic organic substances such as dioxins, pesticides, etc.
Desorbs from the solid phase with little energy under normal pressure,
It can purify contaminated soil and slurry.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a purification device according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram of a two-phase model of an aqueous phase and a soil.

FIG. 3 is a graph of a model equation.

FIG. 4 is a graph showing the result of a two-phase model in which a certain contaminated soil is inverted and stirred in water.

FIG. 5 is a graph showing the results of a two-phase model obtained by subjecting the contaminated soil to reverse stirring and ultrasonic treatment in the presence of a surfactant.

6 is a graph showing a ratio F of a weak adsorbate after performing the processing shown in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reaction tank 2 Processing object 3 Supply system 4 Drug supply system 5 Adsorbent supply system 6 Circulation system 7 Discharge system 8 Valve 9 Ultrasonic wave transmitter 10 Waveguide 11 Ultrasonic oscillator a Spherical resin

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Koichi Nakagawa 2-47, Shishitsuhigashi, 1-chome, Namiwa-ku, Osaka-shi, Osaka F-term (reference) 4D004 AA41 AB06 AB07 CA12 CA15 CA40 CA44 CA47 CA50 CB01 CB42 CB44 CC05 CC17 4D037 AA11 AB14 BA26 BB08 CA01 4D059 AA18 BH01 BH08 BK22 CA23 DB40

Claims (1)

[Claims] 1. A spherical resin having an ability to adsorb hydrophobic organic substances is added to a solid-liquid mixed phase treatment object stored in a reaction tank, and the spherical resin floating near the water surface in the tank is circulated to the bottom of the tank. While circulating the spherical resin in the tank, the solid phase is irradiated with ultrasonic waves from the ultrasonic wave transmitter placed in the tank to the object to be processed, and the hydrophobic organic substance is removed from the solid phase by the vibration extraction action. Desorbs by transferring to the liquid phase, preventing re-adsorption of the hydrophobic organic substance to the solid phase by bonding the surfactant and the hydrophobic organic substance, and adsorbing the desorbed hydrophobic organic substance to the spherical resin. A method for purifying contaminated soil and slurry.