JP3522010B2 - Pressurized downward injection type multi-stage ozone contact tank - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a downward injection type multi-stage ozone contact tank useful for application to an ozone processing apparatus as a method for treating water and sewage, and a control method therefor.

[0002]

2. Description of the Related Art In recent years, water pollution in rivers and lakes is advancing along with the deterioration of the water environment in urban areas, and it is only possible to combine conventional coagulation sedimentation, sand filtration and chlorine treatment into raw water for tap water. The present situation is that there are limits to the chromaticity and odor removal effects of. In particular, about 70% of the water source used as tap water in Japan depends on lake water, dam water, and river water called surface water, and these lake water and dams are actively used for biological activities associated with eutrophication. There is a musty odor or algae odor due to liquefaction. On the other hand, the organic water and ammonia nitrogen contained in various effluents flow into the river water,
It cannot be expected that these influents will be completely purified by the natural purification action of the river.

[0003] In order to deal with the deterioration of water quality of the water source due to such rapid economic growth, prechlorination is generally adopted, but trihalomethane which is an organic chlorine compound generated in the water purification process adopting prechlorination. It is known that (THM) has carcinogenicity. In order to eliminate mold odors and algae odors from such water sources, and as a countermeasure against carcinogenic substances such as trihalomethane, an advanced water purification system that introduces ozone treatment or a combined treatment of ozone treatment and activated carbon treatment into the treatment process of water purification is considered. Has been done.

Ozone gas has an action of oxidizing and removing dissolved harmful substances dissolved in water by its own strong oxidizing power, and is recently used not only for clean water but also for sewage treatment. However, since ozone treatment costs about twice as much as chlorine treatment, it is required to further enhance the treatment effect of ozone gas. Therefore, by creating innumerable minute ozone gas bubbles, the ozone treatment of water and ozone gas is increased. It is an essential requirement to improve contact efficiency and efficiently dissolve and absorb ozone gas in water.

Conventionally, as a means for increasing the contact efficiency and absorption efficiency of ozone gas, a diffuser type ozone reaction tank or a downward injection type ozone reaction tank (U-tube type ozone reaction tank) has been known. As an example of the air diffuser type ozone reaction tank, for example, “water treatment technology using ozone” (Soumiya Isao,
The Pollution Control Technology Society, May 1989) discloses an example of an up / down counterflow type ozone reactor as shown in FIG.

That is, in this example, partition walls 2 and 2 rising from the bottom surface and partition walls 3 and 3 hanging from the top surface are arranged inside the ozone reaction tank 1, and the partition walls 2 and 3 form the gas phase portion. A plurality of overflow type reaction chambers that are separated and have liquid phase portions communicating with each other are configured.

An air diffuser 4.4 made of ceramic or the like having fine holes of several tens of μm is arranged near the inner bottom surface of each chamber, and ozone gas obtained from an ozone generator (not shown) is supplied to the air diffuser 4. When the water to be treated and the ozone gas, which have been fed into the inlet 4 and come into contact with the ozone gas, come into contact with each other as a counter flow as shown by arrows A and A, the contact efficiency of the ozone gas is increased and the ozone treated water 10 flows out.

On the other hand, the lower injection type ozone reaction tank (U-tube type ozone reaction tank) is also called as an injector type ozone contact tank, and as shown in FIG. And the ozone gas obtained by the ozone generator 7 is supplied to the inner pipe 6 through the gas discharge pipe 8.
Sent from the top of the. Then, the water to be treated and the ozone gas flowing in from the inlet 5 on the side of the ozone gas reaction tank 1 are continuously brought into contact with each other in the inner pipe 6 as a downward flow to carry out a desired ozone treatment, and the outside of the inner pipe 6 is kept as it is. It rises along the wall surface and flows out as ozone-treated water 10 from the upper part of the ozone reaction tank 1. The unreacted ozone gas is sent to the exhaust ozone treatment device 9 and cleaned.

The ozone reactor 1 has a length of 20 in the vertical direction.
It grows up to -30 meters, which keeps the water pressure in the inner tube 6 at a level of 2.0 to 2.5 (kgf / cm ² ).

This U-tube type ozone reactor has an inner tube 6
The gas-liquid contact effect between the ozone gas and the water to be treated is enhanced by the turbulent flow generated in the above, and the water pressure that increases as the ozone gas flows down in the inner pipe 6 promotes the dissolution of the ozone gas in water. The ozone dissolution efficiency is improved by 5 to 10% compared to the system, and the contact time between ozone gas and water to be treated can be increased about 5 times or more and the residence time in the reaction tank is shortened to 1/5 or less. It has the feature that it can be done. Further, since the ozone reaction tank is vertically long, it has an advantage that the installation space of the ozone treatment facility can be 1/5 of that of the diffuser tube system.

By using such an ozone reaction tank,
Ozone gas, which has a much stronger oxidizing power than chlorine, removes the off-flavor and chromaticity of the water to be treated and oxidizes and removes harmful substances. Research Lecture Lecture No. 7
6 to 77, Toriyama et al., "Organic matter removal characteristics of U-tube type ozone contact tank").

On the other hand, the "accelerated oxidation treatment method" (abbreviated as AOP) has been considered for the purpose of increasing the oxidizing power of ozone. This AOP is roughly classified into O ₃ / H ₂ O ₂ (hydrogen peroxide) treatment and O ₃ + UV (ultraviolet irradiation) combined treatment. These combined treatments are characterized by shortening the treatment time and reducing the size of the treatment equipment. In particular, the O ₃ / H ₂ O ₂ treatment has been put to practical use in Europe and the United States.

All of the above-mentioned combined treatments use ozone to OH.
Although it is a method of promoting oxidation by generating radicals (indirect reaction), there is a group of organic substances that is more reactive in direct reaction with ozone (film reaction) than in OH radicals. (For example, fulvic acid). Therefore, when the combined treatment with ozone is applied, it is necessary to set the treatment process in consideration of whether a clear direct reaction is used or an indirect reaction accompanied by OH radical generation is used.

[0014]

However, in the ozone reaction tank used in the above-mentioned advanced water purification system and the like, a device for increasing the absorption efficiency of ozone gas with respect to the water to be treated has not been established. There is a possibility that the phenomenon of deterioration may occur, and there is a problem that the cost increases due to the increase in size of the device.

For example, in the air diffusion tube type ozone reaction tank shown in FIG. 6, iron or manganese oxidized by ozone gas adheres to the surface of the air diffusion tube 4 as the treatment progresses, and the air diffusion tube 4
There is a risk of causing a decrease in ozone absorption efficiency over time due to the clogging of the gas, and there is a problem that it is necessary to replace the air diffusing tube itself in response to this phenomenon. Furthermore, in order to obtain a sufficient reaction time with ozone gas, the reaction tank must be enlarged, which leads to an increase in the cost required for equipment and the like, and a large site area for installing the device is required. It is difficult to use in areas where it is difficult to secure land such as water purification plants in urban areas.

On the other hand, the U-tube type ozone reaction tank shown in FIG. 7 has an ozone dissolution efficiency improved by about 5 to 10% as compared with a diffuser tube type ozone reaction tank, and the ozone gas and the water to be treated are The contact time can be made longer than 5 times, and the residence time in the reaction tank can be shortened to 1/5 or less, but as described above, the water depth of the ozone reaction tank is 20 to 30 meters. Since it is growing rapidly, there is a problem that the construction work of the facility becomes more complicated than that of the air diffuser method, and further, the removal of the deposits stored in the reaction tank and the cleaning of the inside of the tank cannot be performed easily. However, even if some trouble occurs in the vicinity of the bottom of the reaction tank, it cannot be immediately treated.

Considering the ozone reaction process from another point of view, the ozone reaction process can be roughly classified into an initial stage in which the diffusion of ozone is rate-controlled and a later stage in which the ozone reaction is rate-controlled. . Therefore, the gas-liquid reaction contact tank should ideally be a device that takes these characteristics into consideration. For example, at the beginning of the ozone reaction, a large contact area and a strong stirring mechanism to increase the diffusion efficiency are provided, and the latter stage of the ozone reaction It is sometimes desirable to have a device that ensures a residence time for obtaining a sufficient reaction.

When applied to the above-mentioned two types of ozone reaction tanks, an injection type ozone reaction tank such as a U-tube type ozone reaction tank is suitable in the initial stage, and a diffusing tube type ozone reaction tank is suitable in the latter period.

On the other hand, O ₃ / in the above-mentioned "promoted oxidation treatment method"
When H ₂ O ₂ treatment is applied to tap water, the control of O ₃ / H ₂ O ₂ ratio injection becomes complicated, and it is necessary to establish a water quality standard for hydrogen peroxide concentration in drinking water. There is a problem that it is easily affected by ions (radical scavenger). On the other hand, the O ₃ + UV treatment requires a UV irradiator corresponding to the scale of purified water, and has a drawback that the cost becomes considerably high.

Therefore, the present invention has been made in view of the above, and the efficiency of absorbing ozone gas with respect to the water to be treated can be increased without increasing the size of the apparatus to reduce the cost. It is an object of the present invention to provide a pressure type downward injection type multi-stage ozone contact tank capable of enhancing the decomposability of hardly decomposable organic substances with the combined use of “.

[0021]

In order to achieve the above object, the present invention provides a multi-stage ozone contact tank and a reaction tank juxtaposed to each other according to claim 1, and an inflow pipe inserted into the multi-stage ozone contact tank. A capillary having an ozone gas injector part in which the diameter of the inflow pipe is partially reduced to a small diameter is formed at the inlet of the water to be treated, and an ozone gas injection nozzle is arranged from above to face the ozone gas injector part. An air diffuser is provided, and the tip opening of the inflow pipe is introduced to a position facing the bottom wall of the contact tank located at the lowermost stage in the multi-stage ozone contact tank, and the pipe of the inflow pipe located near this bottom wall is introduced. Ozone treatment with a multi-stage ozone contact tank through a hydrogen peroxide supply pipe from the side of an inflow pipe located near the upper part of the sharp reduction part Water juxtaposed Providing flowed into 応槽 which was to obtain the ozonated water to remove organics pressure type lower injection multistage ozone contact tank.

According to the second aspect, an ultraviolet irradiation lamp is arranged inside the reaction tank, and the ozone-treated water that has passed through the multi-stage ozone contact tank is introduced into the juxtaposed reaction tanks and dissolved in the water by ultraviolet irradiation. Hydrogen peroxide is generated from ozone which is present to remove organic substances. According to claim 3, a catalyst contact tube is housed inside the reaction vessel,
Ozone-treated water that has passed through the multi-stage ozone contact tank is made to flow into a juxtaposed reaction tank to promote the oxidation reaction in the process of contacting the catalyst contact tube.

Further, according to claim 4, an ultraviolet irradiation lamp and a catalyst contact tube are arranged inside the reaction tank, and the ozone-treated water which has passed through the multi-stage ozone contact tank is caused to flow into the juxtaposed reaction tanks to emit ultraviolet light. A pressurized downward injection type multi-stage ozone contact tank is configured to generate hydrogen peroxide from ozone dissolved in water by irradiation and to accelerate an oxidation reaction in the process of contacting with a catalyst contact tube.

According to the lower injection type multi-stage ozone contact tank according to the first aspect, the water to be treated is injected by the ozone gas injector section of the capillary diffuser provided in the middle of the inflow pipe. Ozone gas is efficiently mixed to form highly dissolved ozone water, and dissolved ozone and hydrogen peroxide react with each other to generate OH radicals, and then hit the bottom wall of the multi-stage ozone contact tank from the tip opening of the inflow pipe, causing turbulent flow. As a result, the contact efficiency between the ozone gas and the water to be treated is increased. Then, the water to be treated is fed into the juxtaposed reaction tanks and, after a predetermined residence time, flows out as ozone treated water.

According to the ozone contact tank of the second aspect, in addition to the above action, hydrogen peroxide is generated from ozone dissolved in water by the irradiation of ultraviolet rays in the reaction tank and reacts with dissolved ozone. Ozone treatment proceeds after OH radicals are generated. Further, according to the ozone contact tank of the third aspect, the oxidation reaction is promoted in the process in which the ozone-treated water that has passed through the multi-stage ozone contact tank comes into contact with the catalyst contact tube in the reaction tank.

According to the ozone contact tank of claim 4, the ozone-treated water that has passed through the multi-stage ozone contact tank produces hydrogen peroxide from ozone dissolved in the water due to ultraviolet irradiation in the reaction tank, and is dissolved. While reacting with ozone to generate OH radicals, the oxidation reaction is promoted in the process of contacting with the catalyst contact tube. Therefore, the reaction in the latter stage due to ozone contact is enhanced, the effect of removing the substance having low reactivity is improved, and the oxidation reaction of the water to be treated is promoted to decompose the hardly decomposable substance.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Various embodiments of a pressure type downward injection type multi-stage ozone contact tank according to the present invention will be described below with reference to the drawings. 1 and 2 are schematic views showing a first embodiment of the present invention, in which 11 is a U-tube type multi-stage ozone contact tank, and 12 is a reaction tank juxtaposed with the multi-stage ozone contact tank 11. .

The multi-stage ozone contact tank 11 is composed of a polymer of block-type contact tanks 11a, 11b, 11c and 11d which are divided into a plurality of stages from the bottom to the top and through which water to be treated can flow. And the ozone-treated water 10 flowing out from the treated water tank 13 provided in the uppermost contact tank 11d.
Flows into the reaction tank 12 side. Reference numerals 14 and 14 denote exhaust ozone gas exhaust pipes.

As shown in FIG. 2, the sampling ports 15a, 1 are respectively provided from the bottom to the side of the block type contact tanks 11a, 11b, 11c, 11d divided into units.
5b, 15c, 15d, 15e, 15f and 15g are provided. Reference numeral 16 is an inflow pipe for the water to be treated 17 fed into the multi-stage ozone contact tank 11, and a capillary air diffuser 18 is provided at the inlet of the water for treatment 17 to the inflow pipe 16.
Is provided, and the tip end portion of the inflow pipe 16 is introduced to a position near the bottom wall of the contact tank 11a located at the lowermost stage in the multi-stage ozone contact tank 11 and located near this bottom wall. A sharp reduction section 19 is provided. Reference numeral 30 denotes ozone gas obtained by an ozone generator (not shown).

As shown in the enlarged view of FIG. 2, the capillary air diffuser 18 has an ozone gas injector 20 formed by an orifice in which the diameter of the inflow pipe 16 of the water to be treated is partially reduced. An ozone gas injection nozzle 21 is arranged from above to face the ozone gas injector unit 20, and the ozone gas 30 is fed into the injection nozzle 21.

A tube made of stainless steel is used for the capillary air diffuser 18, and the reduction ratio of the tube diameter for forming the orifice is experimentally obtained.

As shown in the enlarged view of FIG. 2, the other rapid contraction portion 19 has a contraction portion 22 formed by an orifice in which the diameter of the inflow pipe 16 is partially reduced to a small diameter.
A hydrogen peroxide supply pipe 23 is inserted from the side of the inflow pipe 16 located in the vicinity of and above. In addition, 24 shown in FIG.
Is an on-off valve that controls the inflow of hydrogen peroxide, 24a
Is the same flow meter.

The length of the U-tube type multi-stage ozone contact tank 11 in the vertical direction is about 5 to 6 meters, and the length of the same portion of the conventional U-tube type ozone reaction tank is 20 to 30 meters. Is substantially shortened, which is a structural feature of the present embodiment in that it is substantially equivalent to the water depth level of a normal diffuser type ozone reaction tank.

The operation and operating principle of the pressurized lower injection type multi-stage ozone contact tank 11 in the first embodiment will be described below. First, as a basic operation, the water to be treated 17 to be subjected to ozone treatment is fed from the side of the capillary diffuser 18 using a pump (not shown), and at the same time, the ozone gas 30 generated by activating the ozone generator is injected into the injection nozzle 21. Supply to. Then, the flow velocity of the water to be treated 17 in the capillary air diffuser 18 in FIG. 2 is increased by the ozone gas injector 20 and the pressure is decreased. At the same time, from the injection nozzle 21 to the ozone gas injector 2
The ozone gas injected to 0 and the water to be treated 17 are efficiently mixed to become highly dissolved ozone water, which flows down while contacting gas and liquid and reaches the rapid contraction portion 19.

A predetermined flow rate of hydrogen peroxide (H ₂ O ₂ ) is fed from a supply pipe 23 above the contraction section 22 in the rapid contraction section 19, and the dissolved ozone and hydrogen peroxide react with each other to promote the reaction. To generate OH radicals. Further, the flow velocity of the water to be treated 17 is increased by the reducing portion 22 and is sent as a descending flow from the tip opening of the inflow pipe 16 to the lowermost contact tank 11a, and hits the bottom wall of the contact tank 11a to be in a turbulent state. And then rises along the outer wall of the inflow pipe 16. The OH radicals are mainly generated in the upflow section.

During the above operation, it is desirable that both the flow velocity and the pressure of the treated water 17 pumped in are high. The reason is to facilitate the transfer of ozone into water after contact with ozone gas and to supplement the pressure loss generated at the orifice portion of the capillary air diffuser 18.

The water to be treated 17 mixed with the ozone gas in this manner flows from the lowermost stage to the upper stage of the contact tanks 11a, 11b, 11c, 11d in block units which constitute the multistage ozone contacting tank 11, The treated water tank 13 provided in the upper block type contact tank 11d flows out as ozone-treated water 10 and flows into the reaction tank 12, and after a predetermined residence time in the reaction tank 12, the treated water 10 is supplied from below.
It flows out as a and is temporarily stored in an ozone-treated water tank (not shown) to prepare for the next step.

The unreacted ozone gas is discharged from the exhaust pipes 14 and 1.
4 is sent to an exhaust ozone treatment device (not shown), decomposed into harmless gas by known thermal decomposition, decomposition using a catalyst, soil decomposition, chemical solution cleaning treatment or activated carbon treatment and is released into the atmosphere. That is, since ozone gas has a strong oxidizing power similar to that of fluorine and is harmful to the human body, it is indispensable to decompose the ozone gas with an exhaust ozone treatment device.

By contacting such ozone gas with the water to be treated, deodorization, decolorization, oxidation and sterilization of ferro-manganese, polycyclic compounds and organic substances such as algae and off-flavors are carried out. The multi-stage ozone contact tank 11 of this embodiment is a block-type contact tank 1 divided into a plurality of stages from the bottom to the top.
Since it is composed of the polymer of 1a, 11b, 11c, 11d, it is possible to add or reduce a block type contact tank as a unit tank as needed. For example, when it is desired to take a long contact time between the ozone gas 30 and the water to be treated 17, it is possible to increase the overall water depth as an ozone contact tank by additionally polymerizing another similar block type contact tank. In addition, if a problem occurs in a part of the contact tank during operation, it is sufficient to take measures such as reducing the contact tank to a block unit or replacing it, without replacing the entire block contact tank. There is an advantage that it can be done.

Further, sampling ports 15a, 15b, 15c, 15d, 1 are provided on the sides of the block type contact tanks 11a, 11b, 11c, 11d divided into the above-mentioned units, respectively.
Since 5e, 15f, and 15g are provided, the water to be treated 17 can be made to flow out by performing opening / closing control of any sampling port, and the contact time with ozone gas can be easily changed. Is.

In the above description of the operation, the removal of the highly reactive organic substances such as humic acid contained in the water 17 to be treated is carried out based on the downward injection method, whereby the diffusion process of the dissolved ozone is rate-determined in the initial stage reaction process. The removal of low-reactivity manganese, polycyclic compounds, etc. is promoted by the ozone reaction in the latter stage where the OH radical reaction is rate limiting.
As described above, the pressurizing downward injection type multi-stage ozone contact tank 11 in the first embodiment is characterized in that it is a contact tank in consideration of the reactivity of organic substances.

Next, a second embodiment of the present invention will be described with reference to FIG. The second embodiment is an example of a pressure-type downward injection type multi-stage ozone contact tank whose main purpose is to accelerate the reaction process in the latter stage where the ozone reaction is rate-controlling and perform the oxidation treatment.
Since the basic configuration is the same as that of the first embodiment shown in FIG. 1, the same reference numerals are given and displayed.

As described above, the removal of the substance having low reactivity is required to promote the reaction process in the latter stage where the ozone reaction is rate-determining. Therefore, in the second embodiment, the first
An ultraviolet irradiation lamp 2 is provided inside the reaction tank 12 in the embodiment.
5, 25 (indicated as UV lamp in the drawing) are arranged, and a power supply voltage is applied to the ultraviolet irradiation lamps 25, 25 from a low pressure mercury lamp power supply 26 installed outside.

According to the second embodiment, the treated water 17 to be subjected to ozone treatment is supplied to the capillary diffuser 18 together with the ozone gas as described in the first embodiment, and the ozone gas injected into the ozone gas injector 20 is injected. It is mixed with and descends into highly dissolved ozone water, and after the highly reactive humic acid and the like are removed in the multi-stage ozone contact tank 11, it flows into the reaction tank 12 as a descending flow and is irradiated with ultraviolet light to generate water. Hydrogen peroxide (H ₂ O ₂ ) is generated from ozone dissolved in the hydrogen peroxide, and OH radicals are further generated from this hydrogen peroxide by ultraviolet rays. Therefore, the above-mentioned O ₃
The removal efficiency of organic substances is enhanced by taking the same reaction process as that of the / H ₂ O ₂ treatment.

Next, a third embodiment of the present invention will be described with reference to FIG. The third embodiment is an example in which the catalyst contact tube 27 made of titanium oxide (TiO ₂ ) is housed and arranged inside the reaction tank 12 in the first embodiment, and the other construction is the same as the second embodiment shown in FIG. Same as the embodiment.

The catalyst contact tube 27 is composed of a mesh-shaped tube formed by using a mold, and is formed as a single tube or an assembly of block-shaped tubes according to the shape of the reaction tank 12. There is an example. The promoted oxidation reaction with the titanium oxide catalyst is performed by the O ₃ / H ₂ O ₂ and O ₃ + U explained above.
It is reported that the oxidation reaction process is different from that of V (ultraviolet irradiation) treatment, and the reaction mechanism consists of substance adsorption on the catalyst and oxidation on the surface of the catalyst (Paillard, H.
Et al., “Prospects Concerning Applications of Catalyt
ic Ozonation in Drinking Water Treatment "Proceedin
See gs of 10th Ozone World Congress, vol1.p313, 1991).

According to the third embodiment, as in the second embodiment, the dissolved ozone water dissolved under high pressure in the multi-stage ozone contact tank 11 is introduced together with the ozone-treated water 10 from the upper part of the reaction tank 12, and the catalyst contact tube is used. The oxidation reaction is promoted in the process of contacting with titanium oxide forming 27. Oxidation promotion by the titanium oxide catalyst is a treatment method that is hardly affected by bicarbonate ions or the like, which are scavengers for OH radical generation.

Next, a fourth embodiment of the present invention will be described with reference to FIG. In the fourth embodiment, the ultraviolet irradiation lamp 25 used in the second embodiment and the third lamp are provided inside the reaction tank 12.
This is an example in which the catalyst contact tube 27 made of titanium oxide (TiO ₂ ) used in the embodiment is housed and arranged together, and a power supply voltage is applied to the ultraviolet irradiation lamp 25 from a low pressure mercury lamp power supply 26 installed outside. Further, the ozone-treated water 10 flowing out from the treated water tank 13 provided in the uppermost block-type contact tank 11d of the multi-stage ozone contact tank 11 is introduced to the vicinity of the bottom wall of the reaction tank 12 through the conduit 28, and the discharge port 29 is introduced. , 29 into the reaction tank 12 as an upward flow.

According to the fourth embodiment, as in the second embodiment, the dissolved ozone water which has been dissolved under high pressure in the multi-stage ozone contact tank 11 is introduced together with the ozone-treated water 10 from the lower part of the reaction tank 12 to contact the catalyst. The oxidation reaction is promoted in the process of contacting the titanium oxide forming the tube 27, and at the same time hydrogen peroxide (H ₂ O ₂ ) is generated from ozone dissolved in water by the ultraviolet irradiation from the ultraviolet irradiation lamp 25. OH radicals are further generated from this hydrogen peroxide by ultraviolet rays, and the removal efficiency of organic substances is enhanced by following the same reaction process as the O ₃ / H ₂ O ₂ treatment described above. It flows out as 10a.

In the fourth embodiment, as the first step, the hardly decomposable organic matter in the water to be treated 17 is easily decomposed by the direct ozone reaction in the lower part of the multi-stage ozone contact tank 11, that is, the boundary film reaction by the dissolved ozone. Is decomposed into components (chromaticity components), and then the second step is dissolved ozone + UV treatment
H radicals are generated to decompose easily decomposed products, and at the same time, organic substances are decomposed by catalytic oxidation reaction caused by contact between dissolved ozone and the catalyst, and as a third step, catalyst + UV
The treatment has an effect of causing a photocatalytic oxidation reaction.
In other words, various reactions such as "direct reaction", "OH radical reaction", "catalytic oxidation reaction", and "photocatalytic oxidation reaction" are caused on the hardly decomposable organic substance to enhance the decomposition action of the hardly decomposable organic substance.

[0051]

As described in detail above, according to the pressurization type downward injection type multi-stage ozone contact tank according to the present invention, the ozone gas in the capillary diffuser provided with the water to be treated in the middle of the inflow pipe. It becomes highly dissolved ozone water by mixing with the ozone gas injected in the injector part, and it is sent into the multi-stage ozone contact tank to improve the contact efficiency, and this treated water is sent into the reaction tank juxtaposed with the ozone contact tank and the predetermined It can be discharged as ozone-treated water after a residence time.
In the ozone contact tank according to claim 2, 3 or 4, the oxidation reaction is promoted during the process of contacting with the catalyst contact tube and ultraviolet irradiation in the reaction tank, and particularly the reaction in the latter stage due to ozone contact is enhanced to improve the reactivity. It is possible to decompose the hardly decomposable substance by improving the effect of removing a substance having a low content and promoting the oxidation reaction of water to be treated.

Therefore, at the initial stage of the ozone reaction with respect to the water to be treated, it is possible to sufficiently enhance the diffusion efficiency based on the pressurized downward injection method to remove highly reactive substances, and at the latter stage of the ozone reaction, the reaction tank is used. Can obtain a sufficient reaction to enhance the ozone treatment effect. Furthermore, "direct reaction" and "OH radical reaction" for persistent organic substances
By causing various reactions such as “catalytic oxidation reaction” and “photocatalytic oxidation reaction”, the decomposition action of the hardly decomposable organic substance can be enhanced.

Unlike the conventional U-tube reaction tank, the multi-stage ozone contact tank of the present invention does not have to be formed to a length of 20 to 30 meters. The absorption efficiency can be increased. Further, unlike the air diffuser system, there is no phenomenon of deterioration in absorption efficiency over time due to clogging due to adhesion of iron or manganese oxidized by ozone gas.

Further, there is no problem that the construction work of the facility is complicated unlike the U-tube type ozone reaction tank, the construction cost can be reduced, and the deposits stored in the reaction tank can be removed or the inside of the tank can be removed. As a result, it is possible to easily perform cleaning, and it is possible to immediately take measures even if an obstacle occurs near the bottom of the reaction tank.

[Brief description of drawings]

FIG. 1 is a schematic view generally showing a first embodiment of a pressure type downward injection type multi-stage ozone contact tank according to the present invention.

FIG. 2 is an enlarged view partially showing a main part of FIG.

FIG. 3 is a schematic diagram generally showing a second embodiment of the present invention.

FIG. 4 is a schematic diagram generally showing a third embodiment of the present invention.

FIG. 5 is a schematic diagram generally showing a fourth embodiment of the present invention.

FIG. 6 is a cross-sectional view of an essential part showing an example of a normal air diffusion tube type ozone reaction tank.

FIG. 7 is a schematic diagram showing the structure of a normal U-tube type ozone contact tank.

[Explanation of symbols]

11 ... Multi-stage ozone contact tank 12 ... Reaction tank 13 ... Treated water tank 14 ... Discharge pipe 16 ... Inflow pipe 17 ... Water to be treated 18 ... Capillary air diffuser 19 ... Sudden reduction section 20 ... Ozone gas injector 21 ... Injection nozzle 23 ... (hydrogen peroxide) supply pipe 25 ... UV irradiation lamp 26 ... Power supply 27 ... Catalyst contact tube 29 ... Dissipation port

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Claims (5)

(57) [Claims] 1. A plurality of stages are divided from the bottom to the top.
Polymer in a block-type contact tank in which treated water can be distributed
The multi-stage ozone contact tank and the reaction tank configured in parallel are arranged side by side, and the pipe diameter of the inflow pipe is partially reduced to a small diameter at the inlet of the treated water to the inflow pipe inserted in the multi-stage ozone contact tank. A capillary diffuser with an ozone gas injector is formed and an ozone gas injection nozzle is arranged from above to face the ozone gas injector. Introduced to a position facing the bottom wall of the contact tank located in, and provided with a rapid compression part where the diameter of the inflow pipe located near this bottom wall is partially reduced to a small diameter, and near the upper part of the rapid compression part. Insert the hydrogen peroxide supply pipe from the side of the inflow pipe located at
A pressurized lower injection type multi-stage ozone contact tank, wherein ozone-treated water that has passed through the multi-stage ozone contact tank is caused to flow into a juxtaposed reaction tank to obtain organically-removed ozone-treated water. 2. A plurality of stages are divided from the bottom to the top.
Polymer in a block-type contact tank in which treated water can be distributed
The multi-stage ozone contact tank and the reaction tank configured in parallel are arranged side by side, and the pipe diameter of the inflow pipe is partially reduced to a small diameter at the inlet of the treated water to the inflow pipe inserted in the multi-stage ozone contact tank. A capillary diffuser with an ozone gas injector is formed and an ozone gas injection nozzle is arranged from above to face the ozone gas injector, and the tip opening of the inflow pipe is placed at the bottom of the multi-stage ozone contact tank. Introduced to the position facing the bottom wall of the contact tank located at, while placing an ultraviolet irradiation lamp inside the reaction tank, the ozone treated water that passed through the multi-stage ozone contact tank flows into the juxtaposed reaction tank. In this way, a pressure-type downward injection type multi-purpose method is used, in which hydrogen peroxide is generated from ozone dissolved in water by ultraviolet irradiation to obtain ozone-treated water from which organic substances are removed. Stage ozone contact tank. 3. Divided into a plurality of stages from the bottom to the top.
Polymer in a block-type contact tank in which treated water can be distributed
The multi-stage ozone contact tank and the reaction tank configured in parallel are arranged side by side, and the pipe diameter of the inflow pipe is partially reduced to a small diameter at the inlet of the treated water to the inflow pipe inserted in the multi-stage ozone contact tank. A capillary diffuser with an ozone gas injector is formed and an ozone gas injection nozzle is arranged from above to face the ozone gas injector, and the tip opening of the inflow pipe is placed at the bottom of the multi-stage ozone contact tank. Introduced to the position facing the bottom wall of the contact tank located at, while the catalyst contact tube is housed inside the reaction tank, the ozone-treated water that has passed through the multi-stage ozone contact tank is placed side by side in the reaction tank. A pressurized lower injection type multi-stage ozone contact tank characterized in that an ozone-treated water from which organic substances are removed is obtained by promoting an oxidation reaction in a process of flowing in and contacting with a catalyst contact tube. 4. Dividing into a plurality of stages from the bottom to the top.
Polymer in a block-type contact tank in which treated water can be distributed
The multi-stage ozone contact tank and the reaction tank configured in parallel are arranged side by side, and the pipe diameter of the inflow pipe is partially reduced to a small diameter at the inlet of the treated water to the inflow pipe inserted in the multi-stage ozone contact tank. A capillary diffuser with an ozone gas injector is formed and an ozone gas injection nozzle is arranged from above to face the ozone gas injector, and the tip opening of the inflow pipe is placed at the bottom of the multi-stage ozone contact tank. Introduced to the position opposite to the bottom wall of the contact tank located at, the UV irradiation lamp and the catalyst contact tube are arranged inside the reaction tank, and the ozone-treated water that has passed through the multi-stage ozone contact tank is juxtaposed. Generated hydrogen peroxide from ozone dissolved in water by UV irradiation, and promotes oxidation reaction in the process of contacting with catalytic contact tube to remove organic matter A pressure type downward injection type multi-stage ozone contact tank characterized in that the ozone treated water described above is obtained. 5. The multistage ozone contact tank is configured such that ozone-treated water flowing out of a treated water tank provided in the uppermost contact tank is allowed to flow into the reaction tank side.
4. The pressurized downward injection multi-stage ozone contact tank according to 4.