JPH0516916B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method and apparatus for improving the efficiency of ozone treatment, particularly an ozone treatment characterized by subjecting an ozone-containing gas to a discharge treatment immediately before adding the ozone-containing gas to water to be treated. The present invention relates to a method and apparatus for improving efficiency. Here, ozone treatment is a general treatment in which decolorization, deodorization, sterilization, or decomposition of organic matter is performed by adding ozone. (Prior Art) So-called ozone treatment methods such as sterilization, decolorization, deodorization, and COD removal of water, sewage, and industrial wastewater that utilize the strong oxidizing power of ozone are well known. Ozone quickly converts into oxygen in water, so it has many advantages since it does not have the problems of generating trihalomethanes, changes in pH, and residual corrosive chlorine or sodium ions that occur when using oxidizing agents such as chlorine. . However, the common method for producing ozone is silent discharge in dry air, which requires equipment costs and electricity costs, making it relatively expensive compared to methods such as chlorination. Therefore, in the current ozone treatment, a method is used to increase the usage efficiency of ozone by increasing the contact area and contact time between the ozone and the object to be treated, but the area required for treatment,
Many problems remain, including running costs. (Problems to be Solved by the Invention) Therefore, the purpose of the present invention is to solve the problem by dissolving ozone,
An object of the present invention is to provide an efficient method and apparatus for ozonating water, which accelerates the reaction rate by using plasma such as corona discharge and increases the utilization rate of ozone. Furthermore, the purpose of the present invention is to improve the utilization efficiency of ozone in the sterilization, decolorization, deodorization, and COD removal of water and sewage water, as well as in the production of sterilized water necessary in the fields of food, medicine, hospitals, LSI manufacturing plants, biochemistry, etc. An object of the present invention is to provide an ozone treatment method and apparatus that enhance the ozone treatment. (Means for Solving the Problems) Thus, the gist of the present invention is to introduce ozone gas prepared in advance outside the system into the treatment system in ozone treatment performed by bringing ozone into contact with the water to be treated. This is a method for improving the efficiency of ozone treatment, which is characterized in that the ozone-containing gas is subjected to a discharge treatment immediately before or at the time of contacting the ozone-containing gas with the water to be treated. According to a preferred embodiment of the present invention, the ozone treatment includes all types of water treatment using ozone, but particularly when the present invention is applied to decolorization, deodorization, sterilization, or decomposition of organic matter, etc. effective. Furthermore, when using a blowpipe for blowing gas, by performing the discharge treatment of the ozone-containing gas inside the tip of the blowpipe, it is possible to perform the discharge treatment immediately before adding the ozone-containing gas to the water to be treated. In that case, a discharge electrode may be inserted into the tip of the blowpipe, and a ground electrode may be provided on the water to be treated to cause discharge between the water to be treated and the discharge efficiency to be increased. Furthermore, according to another aspect of the present invention, the ozone-containing gas is caused to come into contact with the flow of the water to be treated while flowing in a countercurrent manner, and the ozone-containing gas is subjected to discharge treatment at that time. Of course, as mentioned above,
The water to be treated may be grounded by connecting it to a ground electrode, and the ozone-containing gas may be applied to a discharge electrode provided in the flow to generate a discharge between the water to be treated and the gas. When performing countercurrent contact as described above, the water to be treated does not flow in a horizontal plane, but falls vertically or flows down an inclined surface, while the ozone-containing gas flows upward from below. From the viewpoint of contact efficiency, it is also desirable to allow the mixture to flow. The discharge treatment is generally a corona discharge treatment or a glow discharge treatment. The power source may be positive, negative, or alternating current. According to another feature of the present invention, the present invention includes a container containing water to be treated, a blowpipe connected to an ozone-containing gas source, and blowing the ozone-containing gas into the water to be treated to bring the ozone into contact with the water to be treated. , an ozone treatment device comprising: a discharge electrode inserted into the tip of the blowpipe; and a ground electrode disposed within the container and near the tip of the blowpipe. Note that the ground electrode may be placed at an appropriate position so as to be electrically connected to the water to be treated, and in that case, the discharge treatment is performed between the water to be treated and the discharge electrode. The tip of the blowpipe may form a discharge space depending on the pressure of the supplied gas, or the tip may be closed with a gas-permeable conductive porous material or an insulating porous material. (referred to as a diffuser balloon)
A discharge treatment may be performed between the electrode and the porous body (or the water to be treated). This gas permeable porous body may be either conductive or insulating, but is preferably insulative so that discharge can occur directly on the liquid surface. According to another aspect of the present invention, the ozone treatment device includes a guide treatment path through which water to be treated flows from one end and discharges the water to be treated from the other end, An ozone-containing gas inlet and an outlet for causing ozone-containing gas to flow in a countercurrent flow, the ozone-containing gas inlet and outlet being disposed along the longitudinal direction of the guide treatment path within the flow area of the ozone-containing gas within the guide treatment path. and an arc electrode electrically connected to the water to be treated. The shape of the guide treatment path is not particularly limited as long as the ozone-containing gas and the water to be treated are brought into contact with each other efficiently, but for example, it may have an inclined or vertical closed gutter-like structure, and may be formed from above. The water to be treated may flow downward, and the ozone-containing gas may flow upward from below. In that case, it is preferable to provide a weir at the top to create a type of reservoir so that overflowing water to be treated flows down the gutter. When the ozone-containing gas flows down the gutter-like portion, a discharge treatment is performed between the ozone-containing gas and the water to be treated. As described above, in the present invention, the method of bringing ozone into contact with the water to be treated during ozone treatment includes blowing an ozone-containing gas, such as ozonized air, into the water to be treated, and introducing the water to be treated into the ozonized air. speech bubble,
Any method may be used, such as diffusion, gas-liquid countercurrent contact in a pipe, or turbulent mixing, and it is sufficient to use a method with good contact efficiency that suits the application and purpose. In addition, the containers that contain the water to be treated are so-called reaction tanks for decolorization, deodorization, sterilization, etc. Examples of these include injector-type reaction tanks, bubble-tower-type reaction tanks, tricary-type reaction tanks, spray-type reaction tanks, and more. There is a contact tank with a stirrer, etc. Note that the general discharge treatment conditions in the present invention are as follows. Voltage (KV): 1 ~ 100 Discharge amount: 1.0 × 10 ^-3 μA/cm ² ~ 1.0 mA/cm ² ), preferably 1.0 × 10 ^-1 ~ 1.0 μA/cm ² Ozonated air passing flow rate (cm/sec ): 1.0×10 ^-2 to 3.0×10 ³ , preferably 0.1 to 300 Ozonized air concentration (mg/): 2.0×10 ^-3 to 80, preferably 0.1 to 10. The present invention will be described in further detail with reference to the following. Figure 1 shows a method for oxidizing and removing organic matter, colored matter, and microorganisms by blowing ozone-containing gas into the water by blowing ozone-containing gas from the tip of the blowpipe using a submerged blowpipe in a container containing water to be treated; FIG. 2 is a schematic explanatory diagram of the device. The water to be treated 10 enters the container 12 through a path 14 and is taken out through a discharge path 16 after being treated. The ozone-containing gas from an appropriate ozone-containing gas supply source 18 containing ozone-containing gas prepared in advance is blown into the water to be treated from a submerged blowpipe 20 immersed in the water to be treated. At the tip of the blowpipe 20, an electrode wire 22 inserted into the tube is arranged with the tip slightly protruding. The electrode wire is connected to the positive electrode, and the container bottom 23 is connected to the negative electrode, which is grounded. When ozone-containing gas is blown into the blowpipe, a type of bubble is generated at the tip of the blowpipe, forming a space 24 surrounded by a wall of the water to be treated. In this case, if the electrode wire does not contact the wall surface of the water to be treated, corona discharge or glow discharge can be performed by applying a voltage, and ozone is released into the space just before contacting the liquid to be treated, as well as in the space at the time of contact. The portion 24 undergoes the discharge treatment. Gas generated by the ozone treatment is discharged through a gas vent 26. FIG. 2 shows another modification of the tip of the blowpipe 20, in which the tip is configured as a diffuser bulb with a structure closed by a conductive or insulating porous body 30,
Electric discharge may occur between the porous body 30 (or the water to be treated) and the inserted electrode wire 22 inside the tip thereof. The discharge-treated ozone-containing gas immediately passes through this porous wall and is blown into the water to be treated. FIG. 3 further schematically shows an example of gas-liquid countercurrent contact, in which the water to be treated flowing in and being supplied from the pipe line 32 is temporarily stored in the upper reservoir 34 by the weir 36. From there, the overflow flows down along the wet wall surface 38 and is discharged from the discharge pipe 39. On the other hand, the ozone-containing gas flows in from the pipe 40 which is the introduction port, flows countercurrently above the flow of the water to be treated flowing down as described above, passes through the upper reservoir 34, and then flows through the pipe 40 which is the discharge port.
is discharged from. A linear electrode 46 is provided along the flow direction in the guide processing tube 44 that forms this wetted wall surface 38.
is arranged in a space within the flow of ozone-containing gas, while the wall surface 38 is grounded via a ground electrode. Therefore, when a voltage is applied between the electrode and the wall surface 38 when ozone and the water to be treated come into contact with each other in a countercurrent flow, a discharge occurs between both contact surfaces, promoting activation and dissolution of ozone, and improving utilization efficiency. is enhanced. Next, the present invention will be further explained by examples. Example 1 In this example, methylene blue was decolorized using the apparatus shown in FIG. However, the tip of the blowpipe is
The insulating porous air diffuser shown in the figure was used. The experimental conditions were as shown in Table 1. The results are summarized in a graph in Figure 4. For example, it takes about 11 minutes to halve the concentration of methylene blue using this method, which means that it is possible to reduce the concentration by about 25% compared to the control time of 14.5 minutes. Therefore, the amount of treatment can be increased or the amount of ozone can be saved. Table 1 Methylene blue concentration: 10ppm Amount of water to be treated: 500ml Gas injection amount: 250ml/min Gas injection time: 40 minutes Ozone concentration: 0.2~0.4mg/, 3.5~6.5mg/Discharge voltage, current: DC-10KV, 12μA dispersion Balloon diameter: 20 mm Average pore diameter: 60 to 70 μm Example 2 In this example, an experiment was conducted to decompose secondary treated water from an actual human waste treatment plant. In this experiment, we investigated the case where the amount of treated water and discharge conditions were kept constant, and the ozone concentration was varied. The experimental conditions were as follows. The results obtained are summarized in Table 3. As is clear from the results shown in Table 3, although there are differences depending on the ozone concentration, it can be seen that in any case, the treatment time is always shortened due to discharge. Table 2 Amount of water to be treated: 500ml Gas injection amount: 250ml/min Gas injection time: 40 minutes Ozone concentration: 0.2~0.4mg/, 3.5~6.5mg/ Discharge voltage, current: DC-10KV, 12μA Diffusion bulb diameter: 20mm Average pore diameter: 60~70μm

【table】

[Table] Table 4 shows the changes in ozone concentration before and after corona discharge at the same flow rate (250 ml/min). It can be seen that the ozone concentration itself did not change even with the discharge treatment according to the present invention.

[Table] The graph in Figure 5 summarizes the above results. (Effects of the Invention) As described above, according to the present invention, the required amount of ozone can be reduced, and therefore the equipment cost and operating cost required to obtain the same utilization rate can be reduced. The utilization efficiency of this ozone is usually expected to improve by approximately 20 to 30%. Furthermore, since the processing time is shortened, it is possible to downsize the processing device, reduce operating time, and increase processing capacity. This reduction in driving time amounts to up to 30%.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of the apparatus according to the present invention;
2 is a schematic explanatory diagram showing a modification of the structure of the tip of the blowpipe in FIG. 1; FIG. 3 is a schematic explanatory diagram showing another device of the present invention; FIG. 2 is a graph showing the results of decolorizing methylene blue using the apparatus shown in FIG. 2; and FIG. 5 is a graph showing the state of decomposition of sodium fremate. DESCRIPTION OF SYMBOLS 10... Water to be treated, 12... Container, 14... Route, 16... Discharge path, 18... Ozone-containing gas supply source, 20... Blowpipe, 22... Electrode wire.

Claims (1)

[Claims] 1. In ozone treatment performed by bringing ozone and water to be treated into contact, ozone gas prepared in advance outside the system is introduced into the treatment system, and immediately before the ozone-containing gas is brought into contact with the water to be treated. Alternatively, a method for improving the efficiency of ozone treatment, which comprises subjecting the ozone-containing gas to discharge treatment upon contact. 2. The method according to claim 1, wherein the ozone treatment is decolorization, deodorization, sterilization, or decomposition of organic matter. 3. The contact between ozone and the water to be treated is carried out by blowing ozone-containing gas through a blowpipe immersed in the water to be treated, and the discharge treatment of the ozone-containing gas is performed within the tip of the blowpipe. 1st
or the method described in paragraph 2. 4. The method according to claim 3, wherein the discharge treatment is performed by inserting a discharge electrode into the tip of the blowpipe and providing a ground electrode in the water to be treated. 5. A patent claim in which ozone and the water to be treated are brought into contact by flowing an ozone-containing gas countercurrently over the flow of the water to be treated, and the discharge treatment of the ozone-containing gas is performed within the flow of the ozone-containing gas. range 1
or the method described in paragraph 2. 6. The method according to claim 5, wherein a discharge electrode is inserted into the flow of the ozone-containing gas and a ground electrode is provided in electrical continuity with the water to be treated. 7. The method according to any one of claims 1 to 6, wherein the discharge treatment is a corona discharge treatment or a glow discharge treatment. 8 A container containing water to be treated, a blowpipe that is connected to an ozone-containing gas source and that blows the ozone-containing gas into the water to bring the ozone into contact with the water to be treated, and a discharge tube inserted into the tip of the blowpipe. An ozone treatment device comprising: an electrode; and a ground electrode disposed within the container and near the tip of the blowpipe. 9. The device according to claim 8, wherein the tip of the blowpipe is made of a gas-permeable conductive porous material, and a discharge treatment is performed between the electrode and the porous material. 10. The method according to claim 8, wherein the tip of the blowpipe is made of a gas-permeable insulating porous material, and a discharge treatment is performed between the electrode and the water to be treated around the porous material. Device. 11 An ozone-containing gas inlet, which is a guide treatment path through which the water to be treated flows from one end and is discharged from the other end, and which allows the ozone-containing gas to flow countercurrently above the flow of the water to be treated in the guide treatment path; A guide treatment path provided with a discharge port, a discharge electrode disposed along the longitudinal direction of the guide treatment path within the region of the flow of the ozone-containing gas, and a ground conductive to the flow of the water to be treated. An ozone treatment device consisting of electrodes. 12. The guide treatment path is in the form of an inclined closed gutter, and when the water to be treated flows down the inclined floor surface, it comes into contact with the ozone-containing gas from below in a countercurrent manner. The device according to item 11.