JP2001300528A - Method for decomposing difficult-to-decompose organic matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decompose a difficult-to-decompose organic matter such as dioxins and agricultural chemicals contained in soil, sludge and slurry at normal temperature and pressure, with a small quantity of energy and without using special chemicals or forming a by-product. SOLUTION: An object 2 to be treated is adjusted in a water content adjusting tank 1 to a specified concentration suitable for the ultrasonic vibration in a specified frequency band. A specified amount of the object 2 with the concentration adjusted is stored in a reaction tank 10, and the slurry of the object 2 is irradiated with an ultrasonic wave in a specified frequency band to vibrate and extract the difficult-to-decompose organic matter from the solid phase of the object 2 and to decompose the organic matter in the liquid phase from an ultrasonic wave generator 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for decomposing a hardly decomposable organic substance, and more particularly to a technique for decomposing a hardly decomposable organic substance contained in soil, sludge, slurry and the like.

[0002]

2. Description of the Related Art Heretofore, as a method for decomposing hardly decomposable organic substances, for example, dioxins in a solid substance have been
Melt processing method to melt under high temperature conditions of more than
A supercritical treatment method in which treatment is performed under high temperature and high pressure conditions of 370 ° C. or more and 22 MPa or more has been confirmed. Alternatively, 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 heated at about 350 ° C. in a nitrogen atmosphere has been confirmed.

[0003]

However, in the above-described structure, the energy consumption for maintaining the conditions of high temperature and high pressure is large, the running cost is high, and the dioxin in the solid phase is formed by using a solvent. When transferring wastes into the liquid phase, by-products such as harmful substances and ecotoxic substances other than dioxins may be generated, and are included in water such as landfill leachate, sewage, human waste, sludge, and slurry. It is difficult to apply the above-mentioned method when decomposing the hardly decomposable organic matter.

[0004] The present invention has been made to solve the above-mentioned problems, and includes dioxins contained in soil, sludge, and slurry.
Provided is a method for decomposing hard-to-decompose organic substances that can decompose hard-to-decompose organic substances such as pesticides at room temperature and pressure with little energy without using special chemicals or by-products. Aim.

[0005]

In order to solve the above-mentioned problems, a method for decomposing a hardly decomposable organic substance according to the present invention adjusts an object to be treated to a predetermined concentration suitable for ultrasonic vibration in a predetermined frequency band. A predetermined frequency that is stored in the reaction tank and exerts the vibration extraction action of the hard-to-decompose organic substance on the solid phase in the work-piece from the ultrasonic transmitter to the object to be processed, and the decomposition action of the hard-to-decompose organic substance on the liquid phase It irradiates ultrasonic waves in a band.

[0006] With the above configuration, the object to be treated is in a state in which a hardly decomposable organic substance such as dioxins is adsorbed on the surface of a solid phase such as soil or is taken in. The ultrasonic waves acting on the solid phase of the object to be processed exert a vibration extraction action of transferring the hardly decomposable organic substance from the solid phase to the liquid phase by vibrating energy.

On the other hand, cavitation bubble cavities are generated by ultrasonic waves acting on the liquid phase of the object to be treated. When the cavity collapses, adiabatic compression produces a unique state of several hundred atmospheres and thousands of degrees, and at the same time, radicals such as hydrogen radicals, oxygen radicals, hydroxy radicals, and nitrogen radicals are generated.

[0008] Of the hardly decomposable organic substances that have moved into the liquid phase, substances that are relatively hydrophilic and contain a large amount of unsaturated bonds are decomposed by reacting with the generated radicals. Organic compounds having a relatively low vapor pressure (for example, trichloroethylene) are taken into the cavity and decomposed at high temperature and high pressure.

Ultrasonic waves having a vibration extraction action and a decomposition action have a frequency in the range of 1 kHz to 1 MHz, and vary depending on the properties of the object to be treated, for example, the type and composition of the hardly decomposable organic matter, and the properties of sludge and soil. Or it depends on the shape of the reaction tank.

[0010] Incidentally, the properties of sludge and soil at the source are not stable, and particularly the water content always fluctuates. On the other hand, water is needed to generate cavities, but the optimal concentration (water content) for generating cavities
Has an appropriate value.

For this reason, the concentration of the object to be treated is adjusted to a predetermined concentration suitable for ultrasonic vibration in a predetermined frequency band, and the concentration of the object to be treated is adjusted to a predetermined frequency band effective for decomposing the hardly decomposable organic substance under this concentration. By irradiating the ultrasonic waves, the decomposition efficiency of the hardly decomposable organic matter can be increased.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a treatment target 2 flowing into a water content adjustment tank 1 is a contaminated soil, sludge, slurry, or the like, and contains a hardly decomposable organic substance such as dioxins and pesticides.

The water content adjusting tank 1 has a supply system 4 having a pump 3 for supplying the object 2 to be treated, a dilution water system 6 having a pump 5 for supplying dilution water for concentration adjustment, and a diluting water system 6 in the tank. A concentration controller 7 for measuring the concentration (moisture content) of the processing object 2 is connected.

The concentration control device 7 controls the driving of the pump 3 of the supply system 4 and the pump 5 of the dilution water system 6 based on the measured water content, so that the input amount of the processing object 2 supplied from the supply system 4 and the dilution The concentration (water content) of the processing object 2 in the tank is adjusted to a predetermined concentration (water content) by appropriately adjusting the amount of dilution water supplied from the water system 6. The predetermined concentration is a value suitable for ultrasonic vibration in a predetermined frequency band described later, differs depending on the physical properties of the processing target object 2, and is obtained in advance as an empirical rule, but is generally in the range of 50 to 95%.

The water content adjusting tank 1 has a stirrer 8 inside, and is connected to a downstream reaction tank 10 through a connecting pipe 9. A discharge system 11 for discharging the processed material is connected to the reaction tank 10, and a stirrer 12 for stirring the object 2 and an ultrasonic transmitter 13 are installed inside the reaction system 10. The ultrasonic transmitter (horn) 13 is connected to the ultrasonic oscillator 1 through a waveguide 14.
5, the ultrasonic oscillator 15 oscillates ultrasonic vibration which exerts a vibration extracting action on the solid phase of the processing object 2 and a decomposition action on the liquid phase. The ultrasonic transmitter 13 may use a vibrator such as a ceramic which oscillates upon receiving a voltage.

The ultrasonic wave transmitted from the ultrasonic transmitter 13 is
Select from the range of 1 kHz to 1 MHz. The frequency of the ultrasonic wave that exerts the vibration extraction action and the decomposition action differs depending on the physical properties of the object to be treated 2, for example, the type and composition of the hardly decomposable organic substance, the properties of sludge and soil, or the shape of the reaction tank 10. It is determined in advance as a rule.

The operation of the above configuration will be described below. The pump 3 is driven to supply the soil / sludge treatment target 2 from the supply system 4 to the water content adjustment tank 1, the pump 5 is driven to supply dilution water from the dilution water system 6, and the agitator 8 is driven. The slurry is generated by stirring and mixing the processing object 2 and the dilution water.

The concentration controller 7 samples the slurry in the tank, measures the water content, controls the driving of the pump 3 of the supply system 4 and the pump 5 of the dilution water system 6 based on the measured water content, and The slurry is adjusted to a predetermined concentration (water content: 50 to 95%) which is set in advance by appropriately adjusting the input amount of the processing object 2 supplied from 4 and the input amount of dilution water supplied from the dilution water system 6.

The processing object 2 whose concentration has been adjusted is supplied to the reaction tank 10 through the connection pipe 9, and a predetermined amount of the processing object 2 is stored in the reaction tank 10. In the reaction tank 10, an ultrasonic wave oscillated by an ultrasonic oscillator 15 is irradiated from the ultrasonic transmitter 13 to the processing object 2 through the waveguide 14 while stirring the processing object 2 by the stirrer 12.

The hardly decomposable organic substances such as dioxins contained in the processing object 2 are adsorbed on the surface of the solid phase such as soil or are taken in the inside. Ultrasonic transmitter 1
The ultrasonic wave irradiated from 3 acts on the solid phase and the liquid phase of the object 2 to be treated, and the ultrasonic wave acting on the solid phase has a vibration extraction action of transferring the hardly decomposable organic matter from the solid phase to the liquid phase by the vibration energy. Exert.

On the other hand, the ultrasonic waves acting on the liquid phase of the processing object 2 generate cavitation bubble cavities in the liquid phase. When this cavity collapses,
The adiabatic compression produces a unique state of several hundred atmospheres and thousands of degrees, and at the same time, radicals are generated. Among the hardly decomposable organic substances that have shifted to the liquid phase, substances that are relatively hydrophilic and contain a large amount of unsaturated bonds are decomposed by reacting with generated radicals. Organic compounds having a relatively low vapor pressure (for example, trichloroethylene) are taken into the cavity and decomposed at high temperature and high pressure.

By the way, the properties of sludge and soil at the source are not stable, and especially the water content always fluctuates. On the other hand, water is needed to generate cavities, but the optimal concentration (water content) for generating cavities
Has an appropriate value.

For this reason, the object 2 to be treated is subjected to a predetermined concentration (water content 50 to 50) in the water content adjusting tank 1 before the ultrasonic irradiation.
(95%), the decomposition efficiency of the hardly decomposable organic matter can be increased.

Ultrasonic waves having a vibration extracting action and a decomposing action have a frequency in the range of 1 kHz to 1 MHz, and differ depending on the properties of the object to be treated, for example, the type and composition of the hardly decomposable organic matter, and the properties of sludge and soil. Or it depends on the shape of the reaction tank.

The ultrasonic wave may be irradiated as a wide band ultrasonic wave including a vibration extracting ultrasonic wave and a decomposing ultrasonic wave, or both ultrasonic waves may be alternately irradiated at predetermined time intervals. Alternatively, both ultrasonic waves may be emitted from separate ultrasonic transmitters.

[0026]

As described above, according to the present invention, a hardly decomposable organic substance is transferred from a solid phase to a liquid phase by an ultrasonic vibration extraction function, and the hardly decomposable organic substance transferred to a liquid phase by a decomposition action. It can be decomposed by reacting with radicals or taken in the cavity and decomposed under high temperature and high pressure.The concentration of the object to be treated is adjusted to a predetermined concentration suitable for ultrasonic vibration in a predetermined frequency band. The decomposition efficiency of the hardly decomposable organic matter can be increased by adjusting the ratio to. Therefore, hardly decomposable organic substances such as dioxins and pesticides contained in soil and sludge can be decomposed at normal temperature and normal pressure with little energy without using special chemicals or accompanying by-products.

[Brief description of the drawings]

FIG. 1 is a schematic view of a decomposition apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Water content adjustment tank 2 Processing object 3 Pump 4 Supply system 5 Pump 6 Dilution water system 7 Concentration control device 8 Stirrer 9 Connection pipe 10 Reaction tank 11 Discharge system 12 Stirrer 13 Ultrasonic transmitter 14 Waveguide 15 Ultrasonic oscillator

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hirokazu Minami 2-47, Shikitsuhigashi, Namiwa-ku, Osaka-shi, Osaka Prefecture Inside Kubota Corporation (72) Inventor Koichi Nakagawa Shikitsu-higashi, Namiwa-ku, Osaka-shi, Osaka 1-Chome 2-47 Kubota Co., Ltd. (72) Inventor Kodai Yoshizaki 1-2-47 Shikitsu Higashi, Naniwa-ku, Osaka-shi, Osaka F-term Co., Ltd. F-term (reference) 4D004 AA41 AB05 AB07 CA50 DA02 4D037 AA11 AA12 AB14 AB18 BA26 BB01 BB02 4D059 AA00 BK22 EA20 EB20

Claims (1)

[Claims] 1. An object to be processed is adjusted to a predetermined concentration suitable for ultrasonic vibration in a predetermined frequency band, stored in a reaction tank, and is difficult to be converted from an ultrasonic transmitter to the object to be processed and to a solid phase in the object to be processed. A method for decomposing a hardly decomposable organic substance, which comprises irradiating ultrasonic waves in a predetermined frequency band that exerts a vibration extracting action on a decomposable organic substance and a decomposing action on a liquid phase on the liquid phase.