KR20030090362A - A combined process and device of ozone and sonication for water/wastewater treatment - Google Patents

Abstract

PURPOSE: Provided are a method and an apparatus for treating wastewater with high efficiency by applying ultrasonic waves to an ozone oxidation reactor to split large ozone bubbles into fine ozone bubbles, thereby increasing contact area between ozone gas and wastewater and thus reducing ozone consumption. CONSTITUTION: The method comprises the step of oxidizing contaminants in wastewater using ozone while applying ultrasonic waves to the ozone to increase dissolving efficiency of ozone into wastewater by splitting large ozone bubbles into fine ozone bubbles, thereby effectively decomposing contaminants. The apparatus comprises an ozone oxidation reactor(7) with a raw wastewater inlet(3) at an upper portion thereof, a treated water outlet(4) at a lower portion thereof, an ozone inlet(1) and a diffuser(5) which are installed at the bottom thereof; and a transducer(8) for irradiating ultrasonic waves to the raw water in the reactor(7) to split ozone bubbles and increase contact area between ozone gas and wastewater.

Description

A combined process and device of ozone and sonication for water / wastewater treatment

The present invention is an ozone treatment process introduced into water purification and sewage and wastewater treatment facilities, and in particular, a method of increasing the solubility of ozone and reducing the amount of waste ozone by increasing the mass transfer of ozone by combining an ultrasonic decomposition process in an ozone contact tank. It is about.

Generally, ozone is used for sterilization, deodorization and removal of BOD, COD and removal of green algae from water and non-toxicity of toxic substances. In order to contact and dissolve ozone in the treated water, gaseous ozone is injected into the liquid phase by using an air diffuser and a nozzle. When ozone in the gaseous state is injected into the lower part of the contact tank by using an air diffuser and a nozzle, ozone bubbles are generated in a state of fine bubbles having a large contact surface area with the treated water near the lower pressure and the diffuser, but the pressure increases as the bubble rises. This decreases, and the surface area and volume ratio of the dissolved bubbles are reduced due to collisions and bonding between the bubbles, resulting in inefficient material transfer.

This is because when the gas forms a small bubble in water, when the bubble forms a larger bubble, the contact surface area with the treated water per unit volume is reduced, thereby reducing the mass transfer. Therefore, the conventional ozone contact tank must have a treatment facility for waste ozone gas which is not dissolved in the treated water and discharged from the ozone bubbles reached to the surface, and requires a high operating cost and a chemical cost.

Another method of wastewater treatment, when using ultrasonic cracking independently for water treatment, can achieve organic decomposition and the formation of oxidizing radicals. Ultrasonic decomposition alone can reduce the molecular weight of organic matter present in the water and create radicals with high oxidation power in the microbubbles generated through cavitation to obtain additional oxidation reactions.

However, when ultrasonic decomposition alone is applied to water treatment and sewage and wastewater treatment, the treatment efficiency is not large compared to the power consumption, and the amount of radicals that can be obtained is also very limited. In addition, cavitation during normal operation is generated by vibration of the transducer, which may reduce the lifetime of the transducer and other reactor materials.

The present invention has been made to overcome the respective problems of ozone contact bath and ultrasonic decomposition in the method of water treatment, the object of the present invention is the wastewater treatment through the increase of solubility by increasing the volume ratio and contact surface area of ozone bubbles. It is to provide an improvement in ability.

Another object of the present invention is to provide a means for relieving overloading of a transducer in order to suppress the reduction of the life of the transducer and other contact bath materials due to the vibration of the ultrasonic transducer.

1 is a side view schematically showing a conventional ozone contact tank.

Figure 2 is a side view schematically showing an ozone-ultrasonic combination process for water treatment according to the present invention.

Figure 3 is a side view schematically showing an ozone-ultrasonic combination process for full-scale water treatment according to the present invention.

Figure 4 is a schematic diagram showing the use of high concentration ozone water generation and dilution according to the present invention.

<Description of the symbols for the main parts of the drawings>

1: ozone inlet 2: waste ozone gas outlet

3: treated water inlet 4: treated water outlet

5: ozone diffuser 6: ozone bubble

7: ozone contact bath 8: ultrasonic generator

9: rectifying wall 10: waste ozone gas treatment facility

11: dilution and mixing tank 12: stirrer

13: By-pass

Hereinafter, with reference to the drawings the present invention for achieving the above object will be described in detail.

The present invention provides a water treatment method for purifying purified water and sewage and wastewater, comprising the steps of contacting the wastewater with ozone gas to oxidize contaminants in the wastewater; And applying ultrasonic waves to the waste water to increase the dissolved efficiency of the ozone gas to form radicals.

In order to reduce the amount of waste ozone gas that is wasted due to its low solubility, which is a disadvantage of the method of contacting and dissolving gaseous ozone in the existing treated water, the large surface area is pulverized to make small bubbles with high surface area. It needs to be enhanced.

Accordingly, the present invention proposes an ozone-ultrasound decomposition combination method which can simultaneously obtain an increase in solubility due to the crushing of ozone bubbles in the treated water and additional decomposition of organic substances.

Ultrasonic generating transducers are mounted inside and outside the contacting tank to project the ultrasonic waves inside the ozone contacting tank to project the ultrasonic waves.

Ultrasonic transducers emit ultrasonic waves inside and outside the contact vessel in the form of probes and plates to crush bubbles that grow while the ozone bubble contacts the treated water through the diffuser.

Therefore, the present invention is designed to radiate ultrasonic waves to reduce the size of ozone bubbles and increase the contact surface area. This increases the solubility of ozone, thereby improving the utilization efficiency of the ozone generated. Incidentally, there is an advantage that the generation of waste ozone is reduced.

In addition, ultrasonic waves independently have the ability to decompose organic matter and form radicals in the radiation of water to the ozone treatment.

On the other hand, in the water treatment apparatus for purifying purified water and sewage and wastewater using the ozone-ultrasonic combination method for the water treatment, the inlet (3) of the treated water in the upper part, the outlet (4) of the treated water in the lower part, An ozone contacting tank (7) having an ozone inlet (1) and an ozone diffuser (5) on the bottom surface; The ozone-ultrasonic combination apparatus for water treatment was installed inside or outside the ozone contact tank, and includes an ultrasonic radiator for applying ultrasonic waves to the treated water.

In the conventional ozone contact method as shown in FIG. 1, after the treated water flows into the inlet port 3 installed at the upper end of the ozone contact bath 7 in the ozone contact bath 7, a gas state generated by an ozone generating device (not shown) outside the contact bath. Ozone is injected into the bubble state through the ozone inlet 1 and the diffuser 5 provided at the bottom of the contact tank.

At this time, the injected ozone bubble 6 is dissolved in the treated water, but as it rises to the surface, the volume increases due to the decrease in water pressure, collision between bubbles, and fusion, thereby reducing the contact surface area with the treated water.

Finally, bubbles that do not combine with the contaminants and reach the water surface are transferred to the waste ozone gas treatment facility 10 through the waste ozone gas outlet at the top of the ozone contact tank. After contacting for a desired contact time, the treated water is drained through the treated water outlet 4 provided at the lower end of the ozone contact tank.

Unlike the prior art, in the present invention, as illustrated in FIG. 2, an ozone bubble 6 injected through an air diffuser 5 by installing a transducer 8 capable of radiating ultrasonic waves inside and outside of an existing ozone contact tank is provided. Is periodically pulverized to maximize the material transfer efficiency by increasing the contact surface area with the treated water.

The use of the amount of ozone gas injected therein can be maximized and the amount of ozone gas discharged through the waste ozone gas outlet 2 can be reduced.

Therefore, it is possible to increase the amount of pollutants that can be oxidized by the same amount of ozone gas, thereby reducing the scale of the waste ozone gas treatment facility 10, and the additional organic material resolution by the ultrasonic generation of the transducer (8). The formation of radicals with strong oxidizing power can be obtained.

Compared with the present application and the prior application filed No. 10-2000-0016801. First, the present invention conceptually uses ozone and ultrasonic waves simultaneously to increase the bubble surface of ozone to the contact surface area with respect to the pulverization volume ratio.

However, the prior application is to first crush the contaminants in the wastewater with ultrasonic waves, convert them into materials of lower molecular weight, and then contact them with ozone in other reactors.

Therefore, while the role of ultrasonic wave in the prior application is irrelevant to ozone contact and is only used for crushing contaminants in the preceding step, the present invention uses ozone and ultrasonic wave simultaneously to increase the dissolved efficiency of ozone and reduce the ozone flying to the waste gas. Let's do it.

In order to increase the treatment capacity of the pollutants as shown in FIG. 3, the apparatus may be provided by connecting several ozone contact tanks of FIG.

In FIG. 4, the concentrated ozone water generated by the above-described method in the ozone contact tank 7 is transferred to the dilution and admixture tank 11 through the treated water outlet 4, and then, the circumferential pipe ( 13) Agitate and dilute the treated water flowing in through it and make contact with ozone water.

According to the present invention, in order to supplement the problems of the conventional ozone contact tank and ultrasonic decomposition, by swelling the external surface of the device that emits ultrasonic waves in the ozone contact by crushing the ozone bubbles to increase the surface area and increase the contact and dissolved efficiency of ozone It can reduce the amount of ozone gas emitted.

In addition, it is operated in combination with oxidizer treatment such as ozone to extend the life of ultrasonic transducers and reactor materials that are always operated at high intensity, thereby reducing corrosion and damage of materials due to cavitation prevention, and addition obtained through ultrasonic decomposition. Economic benefits can be gained from the formation of radicals.

Claims (3)

In the water treatment method for purifying purified water and wastewater, Contacting the ozone gas with the wastewater to oxidize contaminants in the wastewater; And applying ultrasonic waves to the waste water to increase the dissolved efficiency of the ozone gas to decompose pollutants and to form radicals. In the water treatment device which purifies purified water and wastewater, An ozone contact tank 7 having an inlet 3 for treated water, an outlet 4 for treated water at the lower part thereof, and an ozone inlet 1 and an ozone diffuser 5 at the bottom thereof; And an ultrasonic radiator installed inside or outside the ozone contact tank to apply ultrasonic waves to the treated water. The method of claim 2, Ultrasonic radiator is an ultrasonic transducer (8) is ozone-ultrasonic combination device for water treatment.