JP2001246364A - Process for separating volatile organic compound from water to be treated - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently separate volatile organic compounds such as trichloroethylene and tetrachloroethylene from water to be treated which contains these volatile organic compounds such as groundwater or industrial wastewater with a simple equipment. SOLUTION: This separation process comprises irradiating water to be treated 2 received in a vessel 1, with ultrasonic waves generated by an ultrasonic generator 8 to volatilize volatile organic compounds contained in the water 2 and the volatilized volatile organic compounds are extracted out of the vessel 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention separates volatile organic compounds from treated water, such as trichlorethylene or tetrachloroethylene, when the treated water is groundwater or industrial wastewater. It is about the method.

[0002]

2. Description of the Related Art Conventionally, in the treatment of groundwater or industrial wastewater, volatile organic compounds such as trichloroethylene or tetrachloroethylene contained therein are separated and removed by treating the treated water with air or the like. In general, bubbling (aeration) of blowing a gas is performed to separate volatile organic compounds in the treated water from the treated water by volatilizing the gas blown into the treated water.

[0003]

However, in this bubbling method, in order to increase the rate of separation of volatile organic compounds from treated water, the amount of bubbling gas blown into the treated water must be increased. In addition, since a large amount of gas is handled, the size of the entire apparatus cannot be avoided, and further, there is a problem that noise and power consumption are increased due to an increase in the size of a blower for pumping air.

In addition, in the bubbling method, although a large amount of gas is discharged from the treated water, the amount of volatile organic compounds contained in the discharged gas is extremely small, so that the volatile gas in the large amount of exhaust gas is volatilized. There is also a problem that a large apparatus and a large running cost are required for post-treatment such as decomposing or adsorbing the volatile organic compound.

An object of the present invention is to provide a method for separating a volatile organic compound which solves these problems.

[0006]

According to a first aspect of the present invention, there is provided a method for irradiating treated water contained in a container with ultrasonic waves by an ultrasonic transmitting and vibrating section. , Volatile organic compounds in the treated water are volatilized from the treated water,
The volatilized volatile organic compound is extracted outside the container. Is the thing.

The method according to claim 2 is characterized in that, in addition to blowing gas into the treated water contained in the container, the treated water is irradiated with ultrasonic waves by an ultrasonic transmission vibration unit to volatilize the treated water. The volatile organic compound is volatilized from the treated water, and the volatilized volatile organic compound is extracted out of the container together with the gas blown into the treated water. "

[0008]

According to the first aspect of the present invention, when the treated water contained in the container is irradiated with ultrasonic waves by the ultrasonic transmission vibration unit, the treated water is violently atomized into a mist. And / or a degassing phenomenon or the like will occur, and even when atomization does not occur, the volatile organic compound having a boiling point different from water contained in the treated water will be higher than the treated water. It will volatilize in the gas phase.

Therefore, the volatile organic compound can be reliably separated from the treated water by extracting the volatilized volatile organic compound out of the container.

[0010] In addition, as described in claim 2, the method of separating by the irradiation of ultrasonic waves is used in combination with the above-mentioned conventional bubbling method, so that the separation of volatile organic compounds can be performed by ultrasonic waves. Since the irradiation and bubbling can be performed synergistically, the amount of the bubbling gas blown into the treated water is incomparable to the conventional case, compared to the case where the separation of the volatile organic compound is performed only by bubbling. In addition to being able to reduce, the separation rate of the volatile organic compound can be greatly improved.

Therefore, according to the first and second aspects of the present invention, it is possible to eliminate the use of gas such as air for separating volatile organic compounds from treated water, or to reduce the use of air or the like. Because gas usage can be significantly reduced,
This has the effect of reducing the size of the entire device, reducing noise, and reducing power consumption.

In addition, by using ultrasonic irradiation and bubbling together, the amount of bubbling gas such as air can be reduced, so that post-treatment such as decomposing or adsorbing volatile organic compounds in the exhaust gas is performed. In this case, the required device can be reduced in size, and the running cost can be significantly reduced.

In particular, in the method of the first aspect, as described in the third aspect, a scavenging gas such as air is introduced into a portion of the container above the liquid level of the treated water, Since the volatile organic compound volatilized from the treated water by the irradiation of the ultrasonic wave is pushed out of the container with the scavenging gas introduced into the container, the gas can be quickly extracted together with the scavenging gas, The separation rate of the volatile organic compounds from the treated water can be further improved.

Further, when the bubbling gas is blown into the treated water in the container as in the second aspect, the bubbling gas is extracted outside the container as the fourth aspect. The gas to be removed is used after removing volatile organic compounds in the gas, or as described in claim 3, a portion above the liquid level of the treated water in the container is used for scavenging air or the like. When introducing a gas, as described in claim 5, by using a gas extracted outside the container as the scavenging gas after removing volatile organic compounds in the gas, the scavenging gas is removed from the treated water. It is possible to reduce the amount of gas newly used in the treatment of the separation of volatile organic compounds, to further reduce the running cost, and to achieve low pollution by reducing the emission of gas to the atmosphere. .

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment.

In this figure, reference numeral 1 denotes a closed-type container in which treated water 2 containing a volatile organic compound such as trichloroethylene or tetrachloroethylene is provided with a treated water supply pipe at the top. The liquid level 2a of the treated water 2 is supplied from a discharge valve 6 provided in a discharge line 6 with a discharge pump 5 from the container 1 by a liquid level meter 4 provided for the liquid level 2a. By controlling the opening and closing of 7,
It is configured to keep a substantially constant height at all times.

On the bottom surface of the container 1, an ultrasonic transmission vibration unit 8 irradiates ultrasonic waves from the ultrasonic transmission vibration unit 8 in a direction from the liquid phase of the treated water 2 in the container 1 to the liquid surface 2a. It is attached to be.

A nozzle 9 for blowing gas sent from a bubbling gas supply pipe 10 into the treated water 2 is provided at the bottom of the vessel 1.
As the bubbling gas, air can be used, and an insoluble and / or inert gas such as argon, oxygen, or nitrogen can be used.

In this configuration, the present inventors put 40 cc of treated water 2 initially containing 4 ppm of trichloroethylene into the vessel 1, and added 2 cc to the treated water 2.
Table 1 shows the results of an experiment in which a high-frequency ultrasonic wave of 2.4 MHz was radiated by the 0-watt ultrasonic transmission vibration unit 8 and the concentration of trichlorethylene at each processing time was measured.

[0021]

[Table 1]

In addition, the present inventors have stated that, in the above-mentioned container 1, the treated water containing 100 ppm of trichlorethylene at the beginning
35 cc, and nitrogen gas is blown into the treated water 2 from the nozzle 9 in a large amount of about 1.5 liters per minute in substantially the same manner as in the conventional bubbling method.
2.4M at 20 watt ultrasonic transmission vibration part 8
Hz, and a 20-watt ultrasonic transmission vibrator 8 while blowing nitrogen gas into the treated water 2 at a rate of 0.25 liters per minute, a smaller amount than the above.
Table 2 shows the results of an experiment in which the remaining amount (%) of trichloroethylene was appropriately measured for each treatment time for the three cases, that is, the case where high-frequency ultrasonic waves of MHz were applied.

[0023]

[Table 2]

As is clear from these tables, by irradiating the treated water with ultrasonic waves, the trichlorethylene contained in the treated water can be surely separated. When performing bubbling on, by using this together with ultrasonic irradiation,
Even if the amount of bubbling gas blown into the treated water is reduced to about 1/6 that of the case using only the conventional bubbling method, trichlorethylene can be reliably separated at a higher rate than before, and volatile organic compounds can be obtained. The separation rate from the treated water can be greatly improved.

Further, since the liquid level 2a of the treated water 2 in the container 1 is configured to have a substantially constant height, the separation performance fluctuates with the fluctuation of the liquid level 2a. Thus, the stability of the separation treatment can be improved.

The bubbling gas blown into the treated water 2 in the container 1 is not limited to the nitrogen gas, but may be oxygen gas, and air may be used as in the conventional case. Of course, other insoluble and / or inert gases such as argon gas can be used.

As described above, the volatile organic compounds volatilized from the treated water 2 in the container 1 into the gaseous phase above the liquid level 2a are supplied from the exhaust pipe 11 connected to the upper part of the container 1 to the suction pump 12 Is extracted to the outside of the container 1 and sent to a conventionally known volatile organic compound removing device 13 by decomposition with ultraviolet rays or adsorption of activated carbon, etc., where the volatile organic compounds are removed. is there.

At the time of the above-mentioned processing, the scavenging gas supply pipe 14 is used to supply an inert gas such as an argon gas or a scavenging gas such as air from the scavenging gas supply pipe 14 to a portion of the vessel 1 above the liquid level of the processing liquid 2. It is configured to introduce gas.

Thus, while the gaseous volatile organic compound volatilized from the treated water 2 by the irradiation of the ultrasonic wave is pushed out of the container 1 by the scavenging gas introduced into the container 1, the scavenging gas is Can be quickly extracted together with the gas, so that the separation rate of volatile organic compounds can be further improved.

Next, FIG. 2 shows a second embodiment.

In the second embodiment, a part or all of the gas discharged from the volatile organic compound removing device 13 in the first embodiment shown in FIG.
The gas is sent to the scavenging gas supply pipe 14 via the pipe 5 and is reused as scavenging gas in the container 1.

FIG. 3 shows a third embodiment.

In the third embodiment, a part or all of the gas discharged from the volatile organic compound removing device 13 in the first embodiment shown in FIG.
The bubbling gas is sent to the bubbling gas supply line 10 through the nozzle 6 and reused as bubbling gas blown from the nozzle 9.

According to the second and third embodiments, by repeatedly using a gas, when using a gas which is expensive, has a high separation efficiency and does not generate new harmful compounds, the amount of the gas used is reduced. Savings can be made, running costs can be further reduced, and gas emissions to the atmosphere can be reduced.

The second embodiment and the third embodiment are combined to form a volatile organic compound removing device 13.
A part or all of the gas exhausted from the gas for scavenging,
It goes without saying that it may be reused for both the bubbling gas.

In the above-described embodiment, the ultrasonic transmission vibrating section 8 is provided on the bottom of the container 1.
Was installed so as to irradiate ultrasonic waves from the liquid phase of the treated water 2 in the container 1 in the direction toward the liquid surface 2a. However, the present invention is not limited to this, and as shown in FIG. ,
By inserting the ultrasonic transmission vibration unit 8 into the container 1 so as to be immersed in the treated water 2 in the container 1, the ultrasonic wave from the ultrasonic transmission vibration unit 8 is applied to the treated water 2 in the container 1.
May be configured to be directly irradiated.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a second embodiment of the present invention.

FIG. 3 is a diagram showing a third embodiment of the present invention.

FIG. 4 is a view showing a modification of the separation container.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Container 2 Treated water 3 Treated water supply line 6 Discharge line 8 Ultrasonic transmission vibration part 10 Gas supply line for bubbling 9 Nozzle 11 Exhaust line 12 Suction pump 13 Volatile organic compound removal device 14 Gas supply line for scavenging Road

 ────────────────────────────────────────────────── ─── Continued from the front page (72) Inventor Yoshiaki Miho 6-7-5 Moundoshima, Nishiyodogawa-ku, Osaka F-term in Sasakura Inc. (Reference) 4D037 AA01 AA11 AB14 BA16 BA23 BB05

Claims (5)

[Claims] An ultrasonic wave is radiated to the treated water contained in the container by an ultrasonic transmission vibrating section to volatilize volatile organic compounds in the treated water from the treated water. And extracting a volatile organic compound from the treated water by extracting air from the container. 2. In addition to blowing gas into the treated water contained in the container, the treated organic water is irradiated with ultrasonic waves by an ultrasonic transmission vibrator to volatilize volatile organic compounds in the treated water from the treated water. And a method of separating the volatile organic compound from the treated water, wherein the volatile organic compound volatilized is extracted to the outside of the container together with the gas blown into the treated water. 3. A process according to claim 1, wherein a scavenging gas such as air is introduced into a portion of the container above a liquid level of the treated water. A method for separating organic compounds. 4. The method according to claim 2, wherein the gas blown out of the container is used as the gas blown into the treated water in the container after removing volatile organic compounds in the gas. A method for separating volatile organic compounds from treated water. 5. The method according to claim 3, wherein the gas extracted outside the container is a volatile gas in the gas as a scavenging gas introduced into a portion above the liquid level of the treated water in the container. A method for separating a volatile organic compound from treated water, wherein the volatile organic compound is used after removing the organic compound.