JP3523743B2 - Pressurized downward injection type ozone contact tank and its control method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressurized downward injection type 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 contact tank or a downward injection type ozone contact tank (U-tube type ozone contact tank) is known. As an example of the air diffuser type ozone contact tank, for example, "Ozone-using water treatment technology" (Soumiya Isao,
The Pollution Control Technology Society, May 1989) discloses an example of a vertical counterflow type ozone contact tank 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 contact tank 1, and the partition walls 2 and 3 form a 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 an injector type ozone contact tank, and as shown in FIG. 14, an inner pipe 6 is provided inside the vertically long ozone contact tank 1. Is arranged, and the ozone gas obtained by the ozone generator 7 is fed from the upper part of the inner pipe 6 through the gas discharge pipe 8. And ozone gas contact tank 1
The water to be treated and the ozone gas flowing in from the side inflow port 5 are continuously contacted as a downward flow in the inner pipe 6 to perform a desired ozone treatment, and then rise along the outer wall surface of the inner pipe 6 as it is. Then, the ozone-treated water 10 flows out from the upper portion of the ozone contact tank 1. The unreacted ozone gas is a waste ozone treatment device 9
It is sent to and cleaned.

The ozone contact tank 1 has a longitudinal length of 20.
It grows up to ~ 30 meters, which keeps the water pressure in the inner pipe 6 at a level of 2.0 to 2.5 (kgf / cm ² ).

This U-tube type ozone contact tank 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 contact tank is vertically long, it has an advantage that the installation space of the ozone treatment facility is 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").

[0012]

However, in the ozone contact tank used in the above-mentioned advanced water purification system, etc., since a control method for increasing the absorption efficiency of ozone gas with respect to the water to be treated has not been established, absorption over time There is a possibility that the phenomenon of reduced efficiency 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 diffuser type ozone contact tank shown in FIG. 13, iron or manganese oxidized by ozone gas adheres to the surface of the air diffuser tube 4 as the treatment progresses, and the time elapses due to clogging of the air diffuser tube 4. There is a risk of causing a general phenomenon of ozone absorption efficiency reduction, and there is a problem in that it is necessary to replace the air diffuser itself in response to this. Furthermore, in order to obtain sufficient reaction time with ozone gas, the contact 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 contact tank shown in FIG. 14 has an ozone dissolution efficiency improved by about 5 to 10% as compared with the diffuser tube type ozone contact tank, and the ozone gas and the water to be treated are The contact time can be longer than 5 times, and the residence time in the contact tank can be shortened to 1/5 or less, but as described above, the water depth of the ozone contact tank is 20 to 30 meters. However, there is a problem that the construction work of the facility is more complicated than that of the air diffusing system, and further, the removal of the deposits stored in the contact tank and the cleaning of the tank cannot be performed easily. However, even if some trouble occurs in the vicinity of the bottom of the contact 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-determining and a late stage in which the ozone reaction is rate-limiting. . 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.

Considering the reaction processes of the two types of ozone contact tanks, the U-tube type ozone contact tank is suitable at the initial stage of the ozone reaction, and the diffuser tube type ozone contact tank is suitable at the latter stage of the ozone reaction. I can say.

Therefore, the present invention has been made in view of the above, and the absorption efficiency of ozone gas with respect to the water to be treated can be increased without increasing the size of the apparatus, the cost can be reduced, and the absorption efficiency can be lowered with time. It is an object of the present invention to provide a pressurized downward injection type ozone contact tank in which a phenomenon does not occur and a control method thereof.

[0018]

In order to achieve the above object, the present invention is divided into a plurality of stages from the lowermost stage to the upper stage according to claim 1, and the water to be treated flows while retaining. Ozone contact tank made of polymer of possible block type contact tank, and a pressurized vortex pump provided in the inflow part of the water to be treated fed into the ozone contact tank, which mixes the water to be treated and the ozone gas with gas and liquid. A variable speed adjuster for adjusting the inflow of treated water, a lower injection pipe vertically inserted in the ozone contact tank, through which the mixed water to be treated falls as a downward flow, and a bottom of the ozone contact tank. The pressure type lower injection type ozone contact tank is provided with a rapid compression section for adjusting the internal pressure of the tube formed in the vicinity of the tip opening of the lower injection tube formed in the portion facing the wall.

Further, according to claim 2, a pressurizing vortex pump for mixing liquid to be treated and ozone gas into the water to be treated is provided, and a variable speed device for adjusting the amount of water to be treated is provided. Pressurized downward injection type ozone contact tank provided with a rapid compression part formed at a portion facing the bottom wall of the ozone contact tank near the tip opening of the lower injection pipe vertically inserted into the ozone contact tank. In, a pressure gauge and a flow meter are provided in the inflow pipe of the water to be treated, and further, an ozone concentration controller for injection, an ozone injection rate controller, a treated water amount controller, and a rapid compression opening controller are provided in the ozone contact tank.
The treated water amount controller outputs the target treated water amount target value to the variable speed device from the preset treated water amount set value and the flow rate of the treated water measured by the above flow meter, and from the treated water amount signal and the ozone injection rate set value. The ozone injection rate controller calculates the injection ozone concentration target value and outputs it to the injection ozone concentration controller. Furthermore, the rapid compression section opening controller calculates it from the pressure signal of the water to be treated by the pressure gauge and the preset pressure setting value. Provided is a control method for a pressurized downward injection type ozone contact tank, which is configured to adjust the opening degree of the rapid compression section based on a target value of the rapid compression section opening degree.

According to claim 3, a pressure gauge and a flow meter are provided in the inflow pipe of the water to be treated, and a dissolved ozone concentration meter is provided in the conduit of the ozone-treated water to set a preset amount of treated water and the above-mentioned set value. The treated water amount controller outputs the treated water amount target value to the variable speed device from the flow rate of the treated water measured by the flow meter, and the dissolved ozone concentration controller injects from the dissolved ozone concentration signal and the preset dissolved ozone concentration set value. 5. A control method for obtaining an ozone concentration target value and outputting it to an injection ozone concentration controller is provided.
According to this, an ultraviolet absorption meter is installed in the ozone treated water pipe, and the treated water amount controller sets the treated water amount target value to the variable speeder based on the preset treated water amount set value and the treated water flow rate measured by the above flow meter. Provided is a control method in which an ultraviolet absorption controller obtains an injection ozone concentration target value from an ultraviolet absorption signal of ozone-treated water and a preset ultraviolet absorption setting value, and outputs it to the injection ozone concentration controller.

[0021] Incidentally, examples of the ozone contact tank, the first reaction chamber of the overflow type liquid phase portion is communicated with each other with the inside of the ozone contact tank vapor portion are separated, the second reaction chamber And an ozone gas injector part in which the diameter of the inflow pipe is partially reduced to a small diameter in the middle of the inflow pipe of the water to be treated sent to the ozone contact tank It is also possible to use a multi-stage ozone contact tank in which a portion is provided and the tip opening of the inflow pipe is introduced to a position near the bottom wall of the first reaction chamber in the ozone contact tank.

According to the pressure type downward injection type ozone contact tank according to the first aspect and the control method according to the second aspect, ozone gas is sent into the water to be treated through the ozone injection pipe to start the pressure vortex pump. By doing so, ozone gas and water to be treated are mixed and made into fine bubbles by this pressurized vortex pump to become highly dissolved ozone water, and the amount of inflow water is adjusted by the variable speed device to be pumped through the inflow pipe, and the inside of the lower injection pipe is The gas and liquid descend while making contact. At this time, the pressure in the pipe is adjusted to a predetermined value by the sudden contraction portion. Then, after passing through the rapid contraction portion formed in the lower injection pipe, the contact wall hits the bottom wall of the contact tank to be in a turbulent state, and the contact efficiency between the ozone gas and the water to be treated is enhanced.

During such an operation, the treated water amount controller inputs the treated water amount set value and the flow rate signal of the treated water measured by the flow meter, and the treated water amount target value output from the treated water amount controller is input to the variable speed device. At the same time, the treated water amount signal is input to the ozone injection rate controller to obtain the injection ozone concentration target value and output to the injection ozone concentration controller. Then, the injected ozone concentration controller issues a control signal to the ozone generator to control the driving state of the ozone generator, and the ozone injection rate is controlled to be constant. Further, the variable speed device issues a rotation speed signal of the pressurized vortex flow pump based on the treated water flow rate target value output from the treated water flow rate controller to control the driving state of the pressurized vortex flow pump. Further, the pressure signal of the water to be treated measured by the pressure gauge is input to the sudden reduction portion opening controller, the sudden reduction portion opening target value is obtained, and output to the sudden reduction portion. The internal pressure of the pipe is maintained at 1.5 (kgf / cm ² ) or more by the opening degree of the rapid contraction portion.

The same control mode can be obtained by using a dissolved ozone concentration controller or an ultraviolet absorption controller instead of the ozone injection rate controller as described in claims 3 and 4. During the above action, at the initial stage of the ozone reaction with respect to the water to be treated, the reaction at the initial stage in which the diffusion efficiency of ozone gas is controlled by the downward injection method to remove highly reactive substances, and the diffusion of ozone gas is rate-determining During the latter stage of the ozone reaction, the reaction in a plurality of stages of block-type contact tanks and the retention of the retention time are carried out to remove the substance having low reactivity, and the latter stage reaction in which the ozone reaction is rate-determining is promoted.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Various embodiments of a pressure type downward injection type ozone contact tank according to the present invention and a control method thereof will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing the basic structure of a pressurized downward injection type ozone contact tank used in the present invention.
Reference numeral 1 denotes an ozone contact tank to which the present embodiment is applied. The ozone contact tank 11 is divided into a plurality of stages from the bottom to the top, and a block-type contact tank 11a through which water to be treated can flow. , 11b, 11c, 11d, 11e, the ozone-treated water 10 flows out from the treated water tank 12 provided in the uppermost contact tank 11e. Reference numeral 13 is a discharge pipe for exhaust ozone gas.

Block type contact tank 1 divided into units
1a, 11b, 11c, 11d, and 11e are provided with sampling ports 14a, 14b, and 14 from the lowermost side, respectively.
c, 14d, 14e, 14f, 14g, 14h are provided.

Reference numeral 15 is an inflow pipe for the treated water 20 fed into the ozone contact tank 11. The inflow portion of the treated water 20 into the inflow pipe 15 has a pressurized swirl pump 16 and a variable speed for adjusting the amount of the inflow water. The device 17 (inverter) is provided. As shown in an enlarged manner in FIG. 2, an impeller portion 16 a is configured in the pressurizing vortex pump 16, and an ozone generator (not shown) in the treated water 20 is provided in the preceding stage of the pressurizing vortex pump 16. An ozone injection pipe 18 for feeding ozone gas from the inside is inserted. This pressurized vortex pump 16
Has three functions of "mixing, forming fine bubbles, and pumping" the ozone gas and the water 20 to be treated.

The inflow pipe 15 is connected to a lower injection pipe 21 vertically inserted in the ozone contact tank 11, and the tip opening of the lower injection pipe 21 is connected to the ozone contact tank 1.
It is introduced up to a position near the bottom wall of the lowermost contact tank 11a in the inside 1. A rapid contraction portion 22 for adjusting the pressure inside the lower injection pipe 21 is formed near the tip opening. As shown in the enlarged view of FIG. 3, the abrupt contraction portion 22 is constituted by an orifice 22a in which the diameter of the lower injection pipe 21 is partially reduced to a small diameter.

The length of the 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 contact tank, which is 20 to 30 meters, is greatly shortened. It is a structural feature of this embodiment that the water depth level is almost equivalent to that of a normal diffuser type ozone contact.

The ozone contact tank 11 in this embodiment is as follows.
The operation during operation and the operating principle will be described below. First, as a basic operation, ozone gas is fed into the water to be treated 20 to be subjected to ozone treatment through the ozone injection pipe 18, and the pressurized vortex pump 16 is started to cause the ozone gas and the water to be treated 20 to be the pressurized vortex pump. 16 impeller parts 16
The mixed water is made into fine bubbles by a and becomes highly dissolved ozone water, and the inflow water amount is adjusted by the variable speed device 17 and the inflow pipe 1
The inside of the lower injection pipe 21 is pressure-fed, and descends while contacting gas and liquid in the lower injection pipe 21. At this time, the pressure in the pipe is 0 due to the sudden contraction portion 22.
It is adjusted to ˜4.0 (kgf / cm ² ).

Then, after passing through the rapid contraction portion 22 formed in the lower injection pipe 21, it hits the bottom wall of the lowermost contact tank 11a to be in a turbulent flow state, thereby increasing the contact efficiency between the ozone gas and the water 20 to be treated. To be

At the time of the above operation, it is desirable that both the flow velocity and the pressure of the water 20 to be treated sent by the pressurized vortex pump 16 are high. The reason is to facilitate the movement of ozone into water after contact with ozone gas, and to supplement the pressure loss generated at the orifice portion of the rapid contraction portion 22.

The water to be treated 20 mixed with the ozone gas in this manner is used as the contact tanks 11a, 11b, 11c, 11d and 11e in units of blocks constituting the ozone contact tank 11.
Flow from the lowermost stage to the upper stage, and after a predetermined residence time, the treated water tank 12 provided at the uppermost stage flows out as ozone-treated water 10 and is temporarily stored in an ozone-treated water tank (not shown). Prepare for the step process. At this time, of course, each sampling port 14a, 14b, 14c, 14d, 1
4e, 14f, 14g and 11h are closed.

Further, the unreacted ozone gas is sent from the exhaust pipe 13 to an exhaust ozone treatment apparatus (not shown), and the known thermal decomposition,
It is decomposed into harmless gas by decomposition using a catalyst, soil decomposition, chemical solution cleaning treatment or activated carbon treatment and 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 the ozone gas with the water 20 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 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 a polymer of 1a, 11b, 11c, 11d, and 11e, it has a feature that a block type contact tank as a unit tank can be added or removed as needed. For example, when it is desired to take a long contact time with ozone gas and water to be treated, it is possible to increase the overall water depth as an ozone contact tank by additionally polymerizing another similar block type contact tank. If a problem occurs in a part of the contact tank during operation, it is only necessary to reduce the contact tank in blocks or replace it, and it is not necessary to replace the entire block contact tank. There is an advantage.

Further, sampling ports 14a, 14b, 14c, 1 are provided on the sides of the block type contact tanks 11a, 11b, 11c, 11d, 11e divided into the above-mentioned units, respectively.
Since 4d, 14e, 14f, 14g, and 11h are provided, it is possible to cause the treated water 20 to flow out by performing opening / closing control of any sampling port, and easily change the contact time with ozone gas. It is possible to

In the above operation, the ratio of the flow rate of water to be treated / the flow rate of ozone gas (abbreviated as L / G ratio) is 10 or more,
It is necessary that the internal pressure of the pipe is 1.5 (kgf / cm ² ) or more. That is, FIG. 4 shows the ozone absorption efficiency η (%) and L /
FIG. 5 is a graph showing the relationship of the G ratio, and FIG. 5 is a graph showing the relationship between the ozone absorption efficiency η (%) and the tube internal pressure (kgf / cm ² ). According to FIGS. 4 and 5, the ozone absorption efficiency is 9
When the target is 0% or more, the L / G ratio is 10 or more and the pipe pressure is 1.5 (kgf / cm ² ) or more under a constant ozone gas flow rate. Therefore, it is necessary to perform the operation satisfying both conditions, and the flow rate of the water to be treated 20 can be reduced by adjusting the inflow amount of the variable speed device 17 and the orifice diameter of the rapid contraction section 22. Since the gas flow rate is not controlled, there is a problem that the target value of the L / G ratio cannot be satisfied. Therefore, it is necessary to limit the variable speed range by controlling the rotation speed by the variable speed device 17.

Further, when the pipe pressure and the amount of the treated water 20 are controlled, mutual interference may occur. Therefore, the pressure setting value is set to 1.5 (kgf / cm ² ) as a threshold value, and the judgment condition is set. It is appropriate that the opening is not adjusted if the threshold value is exceeded.

Next, a control example 1 in this embodiment will be described with reference to FIG. 11 in the figure is the ozone contact tank, 16
Is a pressurizing vortex pump, and 15 is an inflow pipe.
5, a pressure gauge 25 and a flowmeter 26 are provided. 27
Is an ozone generator, 28 is an injected ozone concentration controller, 29 is an ozone injection rate controller, 30 is a treated water amount controller, and 31 is a sudden contraction portion opening controller.
The sudden contraction portion opening controller 31 is a controller for changing the diameter length of the orifice 22a (inner diameter contracting portion) in the sudden contraction portion 22. The configurations of the ozone contact tank 11 and the pressurizing vortex pump 16 are as described with reference to FIG.

According to the control example 1, the treated water amount controller 30 receives the treated water amount set value 35 and the flow rate signal of the treated water 20 measured by the flow meter 26, and outputs the treated water amount controller 30. Target amount of treated water 36
Is input to the variable speed device 17, and the amount of water to be treated 3
7 is input to the ozone injection rate controller 29. The ozone injection rate controller 29 obtains an injection ozone concentration target value 39 from the ozone injection rate set value 38 and the treated water amount signal 37, and outputs it to the injection ozone concentration controller 28.

The injected ozone concentration controller 28 controls the control signal 40 for the ozone generator 27 based on the above input data.
Is generated to control the driving state of the ozone generator 27. The normal control signal 40 is an electric power value, and the ozone generator 2
The amount of ozone generated from the ozone generator 27 is input to the No. 7 and measured by the flow meter 41 and fed back to the injected ozone concentration controller 28. Therefore, this control example 1 is based on the constant ozone injection rate control.

The variable speed device 17 issues the rotation speed signal 42 of the pressurizing vortex pump 16 based on the treated water amount target value 36 output from the treated water amount controller 30,
The driving state of the pressurized vortex flow pump 16 is controlled. Further, the pressure signal 43 of the water to be treated measured by the pressure gauge 25
Is input to the rapid compression portion opening controller 31, the rapid compression portion opening controller 31 obtains the rapid compression portion opening target value 45 from the pressure signal 43 and a predetermined pressure set value 44 to determine the rapid compression portion opening degree. 22 is output. The pipe pressure is set to 1.5 (kgf / cm ² ) or more as described above by the opening degree of the abruptly contracting portion 22.

Next, a control example 2 in this embodiment will be described. Generally, the solubility of ozone gas follows Henry's law, and its solubility is proportional to the partial pressure. When this Henry's law is verified in the pressure type downward injection type ozone contact tank, the result of FIG. 7 is obtained. FIG. 7 shows the pipe pressures of 4.0, 2.0, and 1.0 (kgf / c), with the L / G ratio, which is the ratio of the flow rate of treated water / the flow rate of ozone gas, and the ozone injection rate being constant.
m ² ), the relationship between the residence time and the dissolved ozone concentration in the present ozone contact tank is shown. The retention time on the horizontal axis is the value obtained by converting the length of the ozone contact tank 11 in the height direction into the retention time. (Min). From FIG. 7, under the condition that the L / G ratio and the ozone injection rate are constant, the dissolved ozone concentration increases as the pipe pressure increases. Therefore, it can be understood that the dissolved ozone concentration constant control can be performed by using the pressure as an operation factor.

As a result, the control example 2 shown in FIG. 8 is realized. Since the basic configuration of the control example 2 is almost similar to that of the control example 1, the same components are designated by the same reference numerals to avoid duplication of description.

That is, in the case of this control example 2, a dissolved ozone concentration controller 32 is provided in place of the ozone injection rate controller 29 in the control example 1, and a pipe line through which the ozone-treated water 10 flows is supplemented. A dissolved ozone concentration meter 33 for providing a function is provided. Other configurations are the same as those in the control example 1.

According to the control example 2, the dissolved ozone concentration controller 32 is inputted with the preset dissolved ozone concentration set value 46 and the dissolved ozone concentration 47 of ozone-treated water as auxiliary data, and injection is made from these data. Calculate ozone target value 39 and inject ozone concentration controller 2
8 and the injected ozone concentration controller 28 issues a control signal 40 to the ozone generator 27 to control the driving state of the ozone generator 27. The following description of the operation is the same as that of the control example 1.

In the present control example 2, the pipe pressure is set to 1.5 to 4.0.
The feature is that the dissolved ozone concentration is kept constant by changing the range of (kgf / cm ² ). However, if the pressurization value does not reach the target dissolved ozone concentration value even within the pressurization range, the injected ozone concentration of the ozone generator 27 can be made variable as an auxiliary function.

Next, a control example 3 in this embodiment will be described. That is, in the control example 2, the pressurization value was the main operation factor, whereas in the control example 3, the pressurization value was constant and the signal obtained from the dissolved ozone concentration meter 33 in FIG. Is a control with the main operating factor. The description of the operation is almost the same as the control example 2 and will not be repeated.

Next, a control example 4 in this embodiment will be described. In the control example 2, the control of the dissolved ozone concentration constant by pressure was proposed, but in the control example 4, the change of the ultraviolet absorbance (UV value) by the pressure was experimentally verified. In this experiment, in order to confirm the effect of pressurization, E2
The change in removal characteristics of 60 was measured. The result is shown in FIG. In the figure, the vertical axis represents the residual rate Co / Ci (outflow concentration / initial concentration) of E260 (ultraviolet absorbance at a frequency of 260 nm), and the horizontal axis converts the respective sampling ports provided in the ozone contact tank 11 into residence times. It is a value.

According to FIG. 9, pressurization of 3.9 (kgf / c
m ² ) under the lower injection pipe discharge part (residence time 20
The removal rate of E260 has reached 53.5% in about (seconds), and the reaction due to residual ozone is not observed in the upflow retention section, which is in an equilibrium state. The ozone injection rate D is 2.39 (mg /
1) and the L / G ratio was 12.55. On the other hand, under the condition of 0.25 (kgf / cm ² ) without pressurization, a rapid removal characteristic is shown in the lower injection pipe discharge part, but there is a tendency to decrease even in the upward retention part, and E260 at the retention time of 7 minutes Has a time rate of 3
It was 8.3%.

From these results, it was found that changes in organic matter removal due to pressurization can be confirmed under the conditions where the L / G ratio and the ozone injection rate are constant. Therefore, if the pressure value is the operating factor, U
Control of constant V value is also possible.

As a result, the control example 4 shown in FIG. 10 was realized. Although the basic configuration of the control is similar to that of the control example 1, in the case of the control example 4, a UV value controller 34 is used instead of the ozone injection rate controller 29 in the control example 1.
Is provided, and a UV meter 50 is provided as an auxiliary function in the pipeline through which the ozone-treated water 10 flows out. Other configurations are the same as those in the control example 1.

According to the control example 4, the preset UV set value 51 and the UV value 52 of the ozone-treated water are input to the UV value controller 34, and the injected ozone concentration target value 39 is obtained from these data. It is input to the injected ozone concentration controller 28, and the injected ozone concentration controller 28 issues a control signal 40 to the ozone generator 27 to control the driving state of the ozone generator 27. The following description of the operation is the same as that of the control example 1.

In this control example 4 as well, the pipe pressure is set to 1.5 to 4.0.
It is characterized in that the UV value is kept constant by varying it in the range of (kgf / cm ² ). However, if the pressurization value does not reach the target UV value even within the pressurization range, the injected ozone concentration of the ozone generator 27 can be made variable.

Next, a control example 5 in this embodiment will be described. That is, in the control example 4 described above, the pressure value is the main operating factor, whereas in the control example 5, the signal obtained from the UV meter 50 in FIG. It is a control that is an operation factor. Operation explanation is for control example 4
Since it is almost the same as, it is omitted.

Next, an example in which the control according to the present invention is applied to a downward injection type multi-stage ozone contact tank will be described. FIG. 11 is a schematic view showing an ozone contact tank 60 previously proposed by the present applicant as Japanese Patent Application No. 7-48002. To briefly explain this configuration, the ozone contact tank 60 rises from the bottom inside the ozone contact tank 60. Partition walls 61, 62 and partition walls 63, 6 hanging from the upper surface
4, 65 are provided, and the inside of the ozone contact tank 60 is divided into the first reaction chamber 66 and the second reaction chamber 6 by these partition walls.
7. The storage chamber 68 is divided. The first reaction tank 6
6, the second reaction tank 67 and the retention tank 68 form a plurality of overflow type reaction chambers and a retention chamber in which the gas phase portion is separated and the liquid phase portions communicate with each other.

Reference numeral 15 is an inflow pipe for the water to be treated 20 sent into the ozone contact tank 60. A capillary air diffuser 70 is provided in the middle of the inflow pipe 15, and the tip opening portion of the inflow pipe 15 is provided. 15a is introduced into the ozone contact tank 60 up to a position near the bottom wall of the first reaction chamber 66. Reference numeral 13 is a discharge pipe for exhaust ozone gas.

27 is an ozone generator, 8 is a gas discharge pipe, and the tip of the gas discharge pipe 8 is extended to a position facing the capillary diffuser 70.

FIG. 2 is an enlarged view showing a specific structure of the capillary air diffuser 70. As shown in the drawing, an ozone gas injector 71 in which the diameter of the inflow pipe 15 of the water to be treated is partially reduced to a small diameter. Is formed, and an ozone gas injection nozzle 72 is arranged from above so as to face the ozone gas injector portion 71.

The length of the ozone contact tank 60 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, which is 20 to 30 meters, is greatly shortened. Has been done.

The downward injection type multi-stage ozone contact tank 60.
As a basic operation of, the treated water 20 is sent to the inflow pipe 15, and the ozone gas generated by activating the ozone generator 27 at the same time is supplied with the gas discharge pipe 8 and the injection nozzle 7.
2 to the capillary air diffuser 70. Then, the flow velocity of the treated water 20 is increased by the capillary air diffuser 70 in which the diameter of the inflow pipe 15 is partially reduced to a small diameter (0.5.
At the same time, the ozone gas injected into the ozone gas injector 71 from the injection nozzle 72 and the water to be treated 20 are efficiently mixed to become highly dissolved ozone water, and the gas and liquid flow down while coming into contact with each other. It is sent as a downward flow into the first reaction chamber 66 from the front end opening 15a of the inflow pipe 15, hits the bottom wall of the first reaction chamber 66, and becomes a turbulent flow state, so that the contact efficiency between the ozone gas and the water to be treated 20 is enhanced. .

The treated water 20 thus mixed with the ozone gas is the first overflow type of the ozone contact tank 60.
It is sequentially sent from the reaction chamber 66 to the second reaction chamber 67 and the retention chamber 68, and after a predetermined retention time elapses, it flows out from the retention chamber 68 as ozone-treated water 10. The control method according to the present invention can also be applied to such a downward injection type multi-stage ozone contact tank 60.

[0064]

As described above in detail, according to the pressure type downward injection type ozone contact tank and the control method thereof according to the present invention, the ozone gas is fed into the water to be treated through the ozone injection pipe before the addition. A high-dissolved ozone water is mixed and made into fine bubbles by a pressure vortex pump, and the amount of inflow water is adjusted by a variable speed device, and then the pipe pressure is adjusted to a predetermined value by a rapid compression unit, so that gas and liquid come into contact with each other. While contacting the bottom wall of the contact tank while descending, the contact efficiency between the ozone gas and the water to be treated can be increased, so that the residence time of a conventional diffuser tube type ozone contact tank is about 15 minutes. In the case of this ozone contact tank, the same processing characteristics can be obtained with a residence time of about 5 to 8 minutes.

In the above action, at the initial stage of the ozone reaction to the water to be treated, the diffusion efficiency is sufficiently increased based on the downward injection method to remove the highly reactive substance, whereby the diffusion of the ozone gas is limited in the initial stage. In the latter stage of the ozone reaction, the reaction in the latter stage of the ozone reaction is controlled by the reaction of multiple stages of block type contact tanks and the retention of the retention time to remove low-reactive substances during the latter stage of the ozone reaction. The effect of being promoted is obtained.

Further, in the case of the conventional deep U-tube type ozone contact tank, the treatment characteristics fluctuate when the water flow rate fluctuates, whereas in the case of the control example 1 of this embodiment, L
/ G ratio is 10 or more, and pipe pressure is 1.5 (kgf / c
By setting m ² ) or more, stable processing characteristics can be obtained. Especially when the target value of the L / G ratio cannot be achieved when the water amount changes significantly, the pipe internal pressure is 1.5 (kgf / cm ² ).
By setting the threshold value to, the optimum ozone injection rate control corresponding to the water amount fluctuation becomes possible. Further, according to the control examples 2, 3 and 4, the dissolved ozone concentration constant control and the UV concentration constant control can be performed by adjusting the lower injection pipe internal pressure based on Henry's law, and the target compared to the diffuser pipe system can be achieved. It takes about 1/2 time to reach the dissolved ozone concentration.
The processing time is reduced.

The ozone contact tank according to the present embodiment is a conventional U
Since it does not have to be formed to a length of 20 to 30 meters like a tube reaction tank, it is possible to increase the ozone gas absorption efficiency for water to be treated without increasing the size of the apparatus. Further, it is possible to prevent a decrease 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 becomes 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 an embodiment of a pressurized downward injection type ozone contact tank according to the present invention.

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

FIG. 3 is an enlarged view partially showing another main part of FIG.

FIG. 4 is a graph showing the relationship between ozone absorption efficiency η (%) and L / G ratio.

FIG. 5: Ozone absorption efficiency η (%) and pipe pressure (kgf /
A graph showing the relationship of cm ² ).

FIG. 6 is a schematic diagram for explaining a control example 1 in the present embodiment.

FIG. 7 is a graph showing the relationship between the residence time and the dissolved ozone concentration in the ozone contact tank.

FIG. 8 is a schematic diagram for explaining a control example 2 in the present embodiment.

FIG. 9 is a graph showing the relationship between the residual ratio Co / Ci of E260 and the ozone retention time.

FIG. 10 is a schematic diagram for explaining a control example 4 in the present embodiment.

FIG. 11 is a schematic diagram generally showing the configuration of a downward injection type multi-stage ozone contact tank to which this embodiment is applied.

FIG. 12 is an enlarged view partially showing a main part of FIG.

FIG. 13 is a cross-sectional view of an essential part showing an example of a normal air diffuser type ozone reaction tank.

FIG. 14 is a schematic view showing the structure of a normal U-tube type ozone contact tank.

[Explanation of symbols]

11 ... Ozone contact tank 11a, 11b, 11c, 11d, 11e ... Block contact tank 12 ... Treated water tank 14a, 14b, 14c, 14d, 14e, 14f, 1
4g, 14h ... Sampling port 15 ... Inflow pipe 16 ... Pressurization vortex pump 17 ... Variable speed device 18 ... Ozone injection pipe 21 ... Lower injection pipe 22 ... Rapid compression section 25 ... Pressure gauge 26 ... Flowmeter 27 ... Ozone generator 28 Injected ozone concentration controller 29 ... Ozone injection rate controller 30 ... Treated water amount controller 31 ... Rapid reduction part opening controller 32 ... Dissolved ozone concentration controller 33 ... Dissolved ozone concentration meter 34 ... UV value controller

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Goto 2-1-1-17 Osaki, Shinagawa-ku, Tokyo Meidensha Co., Ltd. (56) Reference JP-A-7-275873 (JP, A) JP-A-4-27 281893 (JP, A) JP-A-8-10779 (JP, A) JP-B-4-74049 (JP, B2) Patent 3491371 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , DB name) ) C02F 1/78 B01F 1/00

Claims (4)

(57) [Claims] 1. An ozone contact tank made of a polymer of a block-type contact tank, which is divided into a plurality of steps from the bottom to the top and through which treated water can flow while staying, and is fed into the ozone contact tank. A vortex flow pump installed in the inflow part of the treated water to mix the treated water and ozone gas and a variable speed device for adjusting the inflow amount of the treated water, and vertically inserted into the ozone contact tank. A lower injection pipe that is disposed and in which the water-gas-mixed treated water falls as a downward flow, and a pipe formed near the tip opening of the lower injection pipe that is formed at a portion facing the bottom wall of the ozone contact tank A pressurizing downward injection type ozone contact tank, comprising: a pressure reducing portion for pressure adjustment. 2. An ozone contact tank is provided with a pressurized swirl pump for mixing liquid to be treated and ozone gas into the water to be treated and a variable speed device for adjusting the amount of water to be treated. Made of a polymer of a block-type contact tank having a rapid compression part formed in a region facing the bottom wall of the ozone contact tank near the tip opening of the lower injection pipe vertically inserted into > In a pressure type downward injection type ozone contact tank, a pressure gauge and a flow meter are installed in the inflow pipe of the water to be treated, and the ozone concentration controller, the ozone injection rate controller, the treated water amount controller, and the rapid compression unit are injected into the ozone contact tank. An opening controller is provided, and the treated water amount controller outputs the treated water amount target value to the variable speed device based on the preset treated water amount set value and the treated water flow rate measured by the flowmeter, and the treated water amount signal And Ozo The ozone injection rate controller obtains the injection ozone concentration target value from the injection rate setting value and outputs it to the injection ozone concentration controller. Furthermore, the pressure signal of the water to be treated by the pressure gauge is rapidly reduced from the predetermined pressure setting value. A method for controlling a pressure type downward injection type ozone contact tank, wherein the opening degree of the rapid compression section is adjusted based on the rapid compression section opening target value obtained by the section opening controller. 3. An ozone contact tank is provided with a pressurized swirl pump for gas-liquid mixing treated water and ozone gas, and a variable speed device for adjusting the amount of treated water flowing into the treated water inflow section. Made of a polymer of a block-type contact tank having a rapid compression part formed in a region facing the bottom wall of the ozone contact tank near the tip opening of the lower injection pipe vertically inserted into > In a pressurized downward injection ozone contact tank, a pressure gauge and a flow meter are installed in the inflow pipe of the water to be treated, and a dissolved ozone concentration meter is installed in the pipeline of the ozone-treated water.
Further, an ozone concentration controller for injection, a concentration controller for dissolved ozone, a controller for treated water amount, and a controller for opening the rapid reduction portion are provided in the ozone contact tank, and the treated water amount set value set in advance and the treated water measured by the flow meter are set. The treated water amount controller outputs the treated water amount target value to the variable speed device from the flow rate, and the dissolved ozone concentration controller obtains the injected ozone concentration target value from the dissolved ozone concentration signal and the preset dissolved ozone concentration set value. Output to the controller, and based on the pressure signal of the water to be treated by the pressure gauge and the target value of the rapid compression portion opening calculated by the controller for the rapid compression portion opening from the preset pressure setting value, the opening of the rapid compression portion is performed. A method of controlling a pressure type downward injection type ozone contact tank, which is characterized in that the degree is adjusted. 4. An ozone contact tank is provided with a pressurized swirl pump for mixing liquid to be treated and ozone gas into the water to be treated and a variable speed device for adjusting the amount of water to be treated. Made of a polymer of a block-type contact tank having a rapid compression part formed in a region facing the bottom wall of the ozone contact tank near the tip opening of the lower injection pipe vertically inserted into > In a pressure-type downward injection type ozone contact tank, a pressure gauge and a flow meter are installed in the inflow pipe of the water to be treated, an ultraviolet absorptiometer is installed in the pipeline of the ozone-treated water, and the ozone injected into the ozone contact tank is further injected. A concentration controller, an ultraviolet absorption controller, a treated water amount controller, and a rapid contraction part opening controller are provided, and the treated water amount controller determines the treated water amount from the preset treated water amount set value and the treated water flow rate measured by the flowmeter. The standard value is output to the variable speed device, the ultraviolet absorption controller calculates the injection ozone concentration target value from the ultraviolet absorption signal of the ozone-treated water and the preset ultraviolet absorption setting value, and outputs it to the injection ozone concentration controller. The opening of the rapid compression section is adjusted based on the pressure signal of the water to be treated by the meter and the rapid compression section opening target value obtained by the rapid compression section opening controller from the preset pressure setting value. A method of controlling a pressure type downward injection type ozone contact tank, which is characterized in that: