JPH0871548A - Method and apparatus for treating aqueous solution containing organochlorine compound - Google Patents

Abstract

PURPOSE: To treat an organochlorine compd. in waste water with good decomposition efficiency by simple equipment easy in maintenance. CONSTITUTION: An aq. soln. containing an organochlorine compd. is irradiated with ultrasonic waves or air is introduced into the aq. soln. or the aq. soln. is aerated by a combination of the irradiation with ultrasonic waves and the introduction of air to expel the organochlorine compd. in the aq. soln. to the upper space and the expelled organochlorine compd. is irradiated with ultraviolet rays in the upper space to be subjected to decomposition treatment. A treatment apparatus is equipped with the container 2 receiving the aq. soln. containing the organochlorine compd. so as to leave a space 6 becoming a vapor phase in its upper part, the ultraviolet lamp 3 arranged in the upper space of the container 2 so as not to come into contact with the aq. soln. and the ultrasonic generator 4 arranged in the vicinity of the container to irradiate the aq. soln. in the container with ultrasonic waves.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for treating organic chlorine compounds contained in waste water.

[0002]

2. Description of the Related Art In the cleaning industry, organic chlorine compounds such as tetrachloroethylene and trichlorethylene are widely used as dry cleaning solvents. When these solvents containing organic chlorine compounds are used for washing, they gradually contain water in the laundry, and are separated into a solvent layer and a layer containing water. After separating both layers,
The solvent layer is reused, and the layer containing water is detoxified and then discharged as wastewater into sewers, etc., but the emission standards are becoming stricter year by year.

As a detoxifying method, air is blown into a waste liquid containing an organic chlorine compound to aerate (bubbling).
To disperse the organochlorine compound into the atmosphere, to adsorb and remove the organochlorine compound using activated carbon, a combination of these methods, and a transparent jacket 21 in the waste liquid 20 as shown in FIG. UV lamp 22 stored
Has been proposed to irradiate the waste liquid 20 with ultraviolet rays to decompose the organic chlorine compounds in the waste water.

[0004]

However, since the aeration method only diffuses the organochlorine compound into the atmosphere, it causes a problem of air pollution. Therefore, an exhaust gas treatment device is further required. In addition, the activated carbon adsorption method is not suitable for wastewater containing a high concentration of organic chlorine compounds because the amount of activated carbon adsorbed is limited, and it is necessary to replace the activated carbon regularly, which makes maintenance difficult. Moreover, there is a drawback that it is difficult to treat activated carbon after adsorption. Furthermore, both methods require a large amount of equipment.

Further, the combined method requires a larger space for equipment and has the drawbacks peculiar to the activated carbon adsorption method. All of these methods require a considerable amount of space and installation costs, and it was difficult to install a treatment facility in a small-scale cleaning shop in the town, not in a large-scale cleaning factory.

The method of irradiating the wastewater containing the organochlorine compound with ultraviolet rays by putting an ultraviolet lamp in the wastewater directly irradiates the wastewater with ultraviolet rays, and therefore the effect is largely dependent on the light transmittance of the wastewater. It depends. That is, the decomposition efficiency is reduced due to the floating substances and coloring substances in the waste water.

Further, when ultraviolet rays are irradiated in wastewater containing an organic chlorine compound, the chlorine ion produced lowers the hydrogen ion concentration (pH) and the aqueous solution becomes strongly acidic, and p
Secondary treatment is required, such as draining waste water after adjusting H.

Further, when ultraviolet rays are irradiated in the waste water containing the organic chlorine compound, the decomposition products gradually adhere to the jacket accommodating the ultraviolet lamps to reduce the efficiency of the ultraviolet lamps. Therefore, maintenance is troublesome, such as the need to clean the jacket frequently.

It is an object of the present invention to provide a method and apparatus for treating organic chlorine compounds in waste water, which has simple equipment, is easy to maintain, and has high decomposition efficiency.

[0010]

In the method for treating an aqueous solution containing an organochlorine compound according to the present invention, the aqueous solution containing an organochlorine compound is irradiated with ultrasonic waves, or air is introduced, or aeration is performed by a combination thereof. The organic chlorine compound in the aqueous solution is expelled to the upper space, and the organic chlorine compound expelled to the upper space is irradiated with ultraviolet rays to be decomposed.

Further, in the apparatus for treating an aqueous solution containing an organic chlorine compound according to the present invention, a container for accommodating an aqueous solution containing an organic chlorine compound, leaving a space in the vapor phase in the upper part, and a space in the upper part of the container. It is configured to include an ultraviolet lamp arranged so as not to come into contact with the aqueous solution, and an ultrasonic wave generation device arranged in the vicinity of the container and irradiating the aqueous solution in the container with ultrasonic waves.

Further, a container for accommodating an aqueous solution containing an organochlorine compound leaving a space in the upper part, an ultraviolet lamp arranged so as not to come into contact with the aqueous solution in the upper space in the container, and an aqueous solution in the container And an air circulation device for sucking the air from the gas phase portion and sending it again to the aqueous solution for circulation.

Further, a container for accommodating an aqueous solution containing an organochlorine compound leaving a space in the upper part, an ultraviolet lamp arranged so as not to come into contact with the aqueous solution in the upper space in the container, and an aqueous solution in the container An air circulation device for blowing air into the aqueous solution, sucking air from the gas phase portion and sending it to the aqueous solution for circulation, and an ultrasonic wave generation device for irradiating the aqueous solution in the container with ultrasonic waves, which is arranged in the vicinity of the container. It is configured.

Further, the cross-sectional area of the gas phase space in the upper part of the container is smaller than the surface area of the aqueous solution.

[0015]

In the treatment method of the present invention, when the aqueous solution containing the organochlorine compound is exposed to ultrasonic waves, air is introduced, or a combination thereof is used, the volatile organochlorine compound is originally volatile. It is expelled to the gas phase of and is irradiated with ultraviolet rays by an ultraviolet lamp installed in the upper space and decomposed to be harmless.

Further, in the processing apparatus having the ultrasonic wave generator of the present invention, an aqueous solution containing an organic chlorine compound is introduced into a container so as not to come into contact with an ultraviolet lamp while leaving a space in the vapor phase at the upper part, and the ultrasonic wave is generated. When the device is irradiated with ultrasonic waves to the aqueous solution in the container, the volatile organochlorine compounds are expelled to the upper space, that is, the gas phase by aeration with ultrasonic waves,
It is decomposed by being irradiated with ultraviolet rays by an ultraviolet lamp installed in the upper space.

In the treatment apparatus having the air circulation apparatus of the present invention, when air is blown into the aqueous solution in the container by the air circulation apparatus, air is sucked from the gas phase portion and sent again to the aqueous solution to be circulated, volatile organic chlorine is generated. The system compounds are expelled to the upper space, that is, the gas phase by aeration by aeration,
It is decomposed by being irradiated with ultraviolet rays by an ultraviolet lamp installed in the upper space.

In the processing apparatus having the ultrasonic generator and the air circulation apparatus of the present invention, air is blown into the aqueous solution in the container by the air circulation apparatus, air is sucked from the gas phase portion and again sent to the aqueous solution for circulation. When ultrasonic waves are applied to the aqueous solution in the container by the ultrasonic generator, the volatile organochlorine compounds are expelled to the upper space, that is, the gas phase by aeration and aeration by the ultrasonic waves, and the ultraviolet rays installed in the upper space. The lamp irradiates ultraviolet rays and decomposes.

Since the cross-sectional area of the gas phase space in the upper part of the container is smaller than the surface area of the aqueous solution, that is, the volume of the space is small, the gas phase organochlorine compound is efficiently converted into ultraviolet rays. Is irradiated.

[0020]

FIG. 1 is a diagram showing an embodiment of the present invention, in which a treatment device 1 for an aqueous solution containing an organic chlorine compound (hereinafter referred to as a treatment device) comprises a container 2 and an ultraviolet lamp 3 arranged in the container 2. And an ultrasonic wave generator 4 arranged near the container 2. Examples of the organic chlorine-based compound to be treated include tetrachlorethylene and trichlorethylene used as a dry cleaning solvent. As this solvent is used for washing, it gradually contains water in the laundry, and is separated into a solvent layer and a water-containing layer. The solvent layer is reused, and the water-containing layer is separated, processed by the processing apparatus 1, and then discarded.

The container 2 is, for example, a closed type container made of stainless steel and has an inlet 2a and an outlet 2b for introducing an aqueous solution 5 containing an organic chlorine compound. An ultraviolet lamp 3 is arranged in an upper space 6 of the container 2, and the ultraviolet lamp 3 is housed in a quartz jacket 3a. The ultraviolet lamp 3 may be an ultraviolet ozone lamp. Ultrasonic generator 4
Has a vibrator 4a and an ultrasonic oscillator 4b, and
a is arranged outside the bottom of the container 2.

An aqueous solution 5 containing an organic chlorine compound is
It is introduced from the inlet 2a of the container 2 to a height not touching the ultraviolet lamp 3. When the oscillator 6 of the ultrasonic generator 4 starts to vibrate, the organic chlorine compound in the aqueous solution 5 containing the organic chlorine compound is partially decomposed by the ultrasonic wave and volatilized originally by the aeration generated by the ultrasonic wave. These organic chlorine-based compounds are discharged to the gas phase of the upper space 6, and the discharged organic chlorine-based compounds are irradiated with ultraviolet rays by the ultraviolet lamp 3 installed in the upper space 6 to emit carbon dioxide, chlorine ions and hydrogen ions. Is decomposed into harmless. The gas in the upper space 6 after the treatment is discharged to the atmosphere.

In the embodiment, the batch process is carried out, but the continuous process may be carried out in which the aqueous solution containing the organic chlorine compound is continuously introduced into the container and discharged.

FIG. 2 is a view showing another embodiment of the present invention. A partition 11 is provided in the upper space 6 inside the container 2 of the processing apparatus 1, and the partition 11 surrounds the jacket 3a of the ultraviolet lamp 3. It is placed in and narrows toward the top. As a result, the upper space 6 in the container is partitioned into a space 12 in the vapor phase and an outer chamber 13. The cross-sectional area of the space 12 in the vapor phase is smaller than the surface area of the aqueous solution, and becomes smaller as it goes upward. Therefore, the organic chlorine-based compound, which has a small volume in the gas phase portion and is expelled from the aqueous solution, is efficiently irradiated with ultraviolet rays. The other structure is the same as that of the embodiment of FIG.

FIG. 3 shows still another embodiment of the present invention, in which an air circulating device is provided instead of the ultrasonic wave generating device. The air circulation device is an air outlet 15 that blows air into the aqueous solution 5, a pump 16 that is provided on the outer periphery of the upper space of the container 2 and circulates the air, and passages 17 and 19 that are arranged in the container 2 and that include pipes and the like. And. The air blown into the aqueous solution 5 in the container 2 from the air blowing port 15 goes out to the space 12 in the vapor phase and rises to the suction port 18.
Then, the solution enters the pump 16 through the passage 19 and passes through the passage 17 and is again sent to the aqueous solution from the air outlet 15 to be circulated. The volatile organochlorine compound in the aqueous solution is expelled to the space 12 by the aeration by such aeration, and is decomposed by being irradiated with ultraviolet rays by an ultraviolet lamp installed in the space 12.

It should be noted that a part of the organochlorine compound is not decomposed and circulates together with air to be dissolved again in the aqueous solution, but since the air is constantly circulated, it may go out to the gas phase again and be irradiated with ultraviolet rays. It is completely decomposed as it is repeated.

FIG. 4 is a view showing another embodiment of the present invention. The processing apparatus of FIG. 3 is further provided with an ultrasonic wave generator 4 similar to that of FIG. The other structure is the same as that of the embodiment of FIG.

<Test Example> An aqueous solution containing an organochlorine compound was treated using each of the treatment devices shown in FIGS. 2, 3 and 4, and the concentration of the organochlorine compound in the aqueous solution changed with time. Was measured. Specifically, tetrachloroethylene 2
4 liters of an aqueous solution containing 00 ppm were treated with each treatment device at room temperature. The container used was made of stainless steel having a diameter of 30 cm and a height of 70 cm, and the ultraviolet lamp used was 14 W. An ultrasonic generator having a frequency of 200 KHz and an output of 200 W was used as the ultrasonic generator, and an air pump of 1.5 liter / min was used as the pump of the air circulation device.

The results are shown in the graph of FIG. 2A, 2B, 3C, and 3C show the results of processing by the processing apparatus of FIG. From FIG. 5, it can be seen that the concentration of tetrachlorethylene in the aqueous solution sharply decreases with time. Regarding the concentration of tetrachloroethylene in the gas phase, when it was measured by a gas chromatograph method, it decreased with the same tendency as in the aqueous solution.

[0030]

INDUSTRIAL APPLICABILITY In the treatment method of the present invention, the organic chlorine compound in the aqueous solution containing the organic chlorine compound is exposed to ultrasonic waves, air is introduced, or aeration is performed by a combination of these, so that the gas phase in the upper space is increased. Since it discharges completely detoxified gas by irradiating organochlorine compounds in the gas phase with ultraviolet rays, there is no risk of polluting the atmosphere, and there is no need for secondary treatment after treatment. Absent.

Further, since the organic chlorine compound is irradiated with ultraviolet rays in the gas phase, the ultraviolet rays are irradiated regardless of the state of the aqueous solution, and the decomposition efficiency is high.

When ultraviolet rays are irradiated in an aqueous solution containing an organic chlorine compound, the pH of the aqueous solution is changed by chlorine ions.
However, in the present invention, the pH of the aqueous solution does not change and the detoxified aqueous solution can be discharged as it is. Also, the detoxified gas phase gas can be discharged as it is.

In the processing apparatus of the present invention, when ultrasonic waves are used, aeration occurs, and at the same time, the organochlorine compound is partially decomposed in the aqueous solution, which accelerates the decomposition rate. Furthermore, the irradiation of ultrasonic waves raises the temperature of the aqueous solution and promotes decomposition.

With the air circulation device, the volatile organochlorine compound is expelled to the upper space, that is, the gas phase by aeration by aeration, and ultraviolet rays are irradiated by an ultraviolet lamp installed in the upper space. , Part of the organochlorine compound is not decomposed and circulates with the air to dissolve again in the aqueous solution, but since the air constantly circulates, it is repeatedly exposed to ultraviolet rays again in the gas phase. Completely decomposed.

When an ultrasonic wave generator and an air circulation device are provided together, ultrasonic waves are applied to the air circulation to make air bubbles blown into the aqueous solution finer and increase the decomposition efficiency of the organochlorine compound.

When the cross-sectional area of the upper space of the gas phase in the container is smaller than the surface area of the aqueous solution, the volume of the gas phase portion becomes small, so that the gas phase organochlorine compound is efficiently converted into ultraviolet rays. Is irradiated. Particularly in the case of combination with air circulation, the flow of air containing an organic chlorine compound closely passes around the ultraviolet lamp, so that the ultraviolet rays are efficiently irradiated.

In the processing apparatus of the present invention, since the ultraviolet lamp is arranged in the upper space, there is little possibility that the ultraviolet lamp will have deposits, the irradiation efficiency of ultraviolet rays does not decrease, and maintenance is easy. is there. It can be treated without being affected by suspended matter in the wastewater or the state of coloring. No need for secondary treatment of wastewater or gas after treatment. The treatment device has a simple structure and has a merit that it can be installed in a small-scale cleaning store or the like because the device can be made small in size and does not take up a lot of space for treating wastewater in a small-scale cleaning store.

[Brief description of drawings]

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

FIG. 2 is a diagram showing another embodiment.

FIG. 3 is a diagram showing another embodiment.

FIG. 4 is a diagram showing another embodiment.

FIG. 5 is a graph showing the results of measurement tests.

FIG. 6 is a diagram showing an example of a conventional processing method.

[Explanation of symbols]

 1 Processing Device 2 Container 2a Inlet 2b Outlet 3 Ultraviolet Lamp 3a Jacket 4 Ultrasonic Generator 4a Transducer 4b Ultrasonic Oscillator 5 Aqueous Solution 6 Upper Space (Upper Space) 11 Partition 12 Space 13 Outer Chamber 15 Air Outlet 16 Pump 17 Passage 18 suction port 19 passage

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location C02F 1/20 ZAB A 1/36 ZAB

Claims (5)

[Claims] 1. An organochlorine compound in an aqueous solution is expelled to an upper space by irradiating an aqueous solution containing the organochlorine compound with ultrasonic waves, introducing air, or aeration by a combination of these, to a space in the upper part. A method for treating an aqueous solution containing an organochlorine compound, which comprises irradiating an ultraviolet ray to the expelled organochlorine compound for decomposition treatment. 2. A container for accommodating an aqueous solution containing an organochlorine compound, leaving a space in the vapor phase above, and an ultraviolet lamp arranged so as not to come into contact with the aqueous solution in the upper space in the container. An apparatus for treating an aqueous solution containing an organic chlorine compound, comprising: an ultrasonic wave generator that is disposed in the vicinity of the container and irradiates the aqueous solution in the container with ultrasonic waves. 3. A container for accommodating an aqueous solution containing an organochlorine compound leaving an upper space, an ultraviolet lamp arranged so as not to come into contact with the aqueous solution in the upper space in the container, and an aqueous solution in the container. An apparatus for treating an aqueous solution containing an organic chlorine compound, comprising: an air circulation device which blows air into the chamber, sucks air from a gas phase portion, and sends the air again to the aqueous solution for circulation. 4. A container for accommodating an aqueous solution containing an organochlorine compound leaving a space in the upper part, an ultraviolet lamp arranged so as not to come into contact with the aqueous solution in the upper space in the container, and an aqueous solution in the container. Organochlorine provided with an air circulation device for blowing air into the aqueous solution, sucking air from the gas phase part and sending it to the aqueous solution for circulation, and an ultrasonic wave generation device which is disposed in the vicinity of the container and irradiates the aqueous solution in the container with ultrasonic waves. For treating aqueous solution containing base compounds. 5. The cross-sectional area of the upper space in the container, which is the gas phase, is smaller than the surface area of the aqueous solution.
An apparatus for treating an aqueous solution containing an organochlorine compound according to any one of 1.