JPH09290280A - Ozone contact tank and control method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the absorption efficiency of ozone in water to be treated and to lower the cost by arranging a pressure volute pump for mixing gaseous ozone and the water to be treated at the inflow part of the water to an ozone contact tank and providing a sharply contracted part for controlling the pressure in a pipe close to the tip opening of a downward injection pipe. SOLUTION: Gaseous ozone is introduced into the water 20 to be treated through an ozone injection pipe 18, a pressure volute pump 16 is started to mix the ozone and the water 20 by the impeller of the pump 16, hence the bubble is micronized to form an ozonized water having a high content of dissolved ozone, the ozonized water is passed through an inlet pipe 15 under pressure with the flow rate controlled by a variable-speed gear 17 and allowed to descend in a downward injection pipe 21 while in contact with the gas. At this time, the pressure in the pipe is optimized by a sharply contracted part 22 provided to the injection pipe 21. The ozonized water passed through the sharply contracted part 22 is collided with the bottom wall of the lowermost contact tank 11a and made turbulent, and hence the gaseous ozone is brought into efficient contact with the water 20.

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 Water pollution in rivers and lakes has been progressing with the deterioration of the water environment in urban areas in recent years. Raw water for tap water can be obtained only by the conventional combination of coagulation sedimentation, sand filtration and chlorination. There is a point where the chromaticity and odor removing action of the odor have a limit. In particular, about 70% of the water sources used as tap water in Japan depend on surface water, such as lakes, dams and river water, and these lakes and dams have active biological activities associated with eutrophication. There is a generation of mold odor and algae odor due to the formation of organic substances and ammonia nitrogen contained in various wastewater into the other river water,
It is impossible to completely purify these inflows by the natural purification action of rivers.

[0003] In order to cope with the deterioration of the water quality of the water source due to such high economic growth, pre-chlorination is generally adopted. Trihalomethane which is an organic chlorine compound generated in a water purification process employing pre-chlorination is used. (THM) is known to have carcinogenicity. In order to eliminate mold odors and algae odors from such water sources and to prevent carcinogens such as trihalomethanes, an advanced water purification system that introduces ozone treatment or a combined treatment of ozone treatment and activated carbon treatment into the operation process of water purification is considered. Has been done.

[0004] Ozone gas has an action of oxidizing and removing dissolved harmful substances dissolved in water by its own strong oxidizing power, and has recently been adopted not only for water supply but also for sewage treatment. However, the cost of ozone treatment is about twice as high as that of chlorination, and it is required to further enhance the effect of ozone gas treatment. Therefore, by forming countless fine ozone gas bubbles, water and ozone gas It is an essential requirement to increase the contact efficiency and to efficiently dissolve and absorb ozone gas in water.

Conventionally, as 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. The air diffuser type ozone contact tank is also called an up-and-down bypass ozone contact tank. For example, “Ozone-using water treatment technology” (Isao Soumiya, Pollution Control Technology Association, 198
(May 9th), an example of a vertically opposed bypass type ozone contact tank as shown in FIG. 6 is disclosed.

That is, in this example, partitions 2 and 2 rising from the bottom and partitions 3 and 3 suspended from the top are disposed inside the ozone contact tank 1, and the gas phase portion is formed by the partitions 2 and 3. A plurality of overflow-type reaction chambers which are separated and whose liquid phase portions communicate with each other are formed.

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. 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 from the inflow port 5 on the side of the ozone gas contact tank 1 are continuously contacted as a downward flow in the inner pipe 6 to perform a desired ozone treatment. It rises along the wall surface and flows out as ozonized water 10 from above the ozone contact tank 1. The unreacted ozone gas is sent to a waste ozone treatment device 9 and is subjected to a cleaning treatment.

The vertical length of the ozone contact tank 1 is 20
The water pressure in the inner tube 6 is maintained 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 step, and the water pressure that increases as the ozone gas flows down in the inner pipe 6 promotes the dissolution of the ozone gas into the water. The ozone dissolution efficiency is improved by 5 to 10% compared to the system, the contact time between ozone gas and the water to be treated can be about 5 times or more, and the residence time in the reaction tank is reduced to 1/5 or less. It has the feature that it can be done. Further, since the ozone contact tank is vertically long, there is an advantage that the installation space of the ozone treatment facility is only 1/5 that of the air diffuser system.

By using such an ozone reaction tank,
Ozone gas, which has much more oxidizing power than chlorine, removes off-flavors and chromaticity of the water to be treated, and oxidizes and removes harmful substances. (For the U-tube type ozone treatment equipment, the 2nd Annual Ozone Association of Japan Research Lecture Series No. 7
Pages 6 to 77, see Toriyama et al., "Organic matter removal characteristics of U-tube 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. 6, as the treatment progresses, iron or manganese oxidized by ozone gas adheres to the surface of the air diffuser pipe 4, and
There is a concern that the ozone absorption efficiency may decrease over time due to clogging of the air, and there is a problem that it is necessary to replace the air diffuser itself in order to cope with the phenomenon. Furthermore, in order to take sufficient reaction time with ozone gas, the contact tank must be enlarged, which leads to an increase in equipment costs and the like, and also requires a large site area for installing the apparatus. It is difficult to adopt in areas where land is difficult to secure, such as water purification plants in urban areas.

On the other hand, the U-tube type ozone contact tank shown in FIG. 7 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 reaction process of ozone from another viewpoint, 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, it is ideal that the gas-liquid reaction contact tank is also a device based on these characteristics.For example, at the beginning of the ozone reaction, it has a large contact area and a strong stirring mechanism to increase the diffusion efficiency, and Sometimes it is 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 an ozone contact tank which improves absorption efficiency of ozone with respect to water to be treated, reduces cost, and does not cause a phenomenon of deterioration of absorption efficiency with time. The purpose is to provide a control method therefor.

[0018]

In order to achieve the above object, the present invention firstly provides a vertical ozone contact tank through which water to be treated can flow while staying, and an ozone contact tank according to claim 1. A pressurized swirl pump provided in the inflow part of the treated water to be fed, for mixing the ozone gas obtained by the ozone generator with the treated water, and a variable speed device for adjusting the inflow amount of the treated water, and ozone. Inside the pipe formed near the tip opening of the lower injection pipe that is inserted and arranged from the upper part of the contact tank and through which the water to be treated falls as a downward flow, and the portion of the lower injection pipe that faces the bottom wall of the ozone contact tank. The ozone contact tank is provided with a pressure-reducing section for pressure adjustment, and a plurality of reaction chambers in which the gas phase section is separated and the liquid phase sections are communicated with each other are provided. Upper and lower bypass type ozone contact tank and each of the above reactions A vertical injection pipe that is vertically arranged in the ozone gas and the water to be treated obtained by the ozone generator flows in through a pressurized swirl pump, a flow control valve, and a flow meter and falls as a downflow. Provided is an ozone contact tank including a sharply reducing portion for adjusting the internal pressure of a pipe formed in the vicinity of a tip opening of a lower injection pipe at a portion facing a bottom wall of the ozone contact tank.

According to a third aspect of the present invention, a dissolved ozone concentration meter and an organic matter concentration meter are arranged in each of the reaction chambers, and the control unit is based on the measured values of the dissolved ozone concentration meter and the organic matter concentration meter and the measured value of the flow meter. Provides a control method for calculating the opening of the flow control valve and the driving condition of the ozone generator to perform the control for optimally adjusting the ozone injection rate and the L / G ratio, and the lower injection pipe according to claim 4 The treated water flow rate / ozone gas flow rate ratio (L / G ratio) is 10 or more, and the pipe pressure is 1.5 (kg
f / cm ² ) or more.

Further, according to claim 5, a vertical bypass type ozone contact tank having a plurality of reaction chambers in which a gas phase portion is separated and a liquid phase portion is communicated with each other, and a vertical bypass chamber in each reaction chamber. A lower injection pipe, which is arranged in a mold and into which the ozone gas obtained by the ozone generator and the water to be treated flow in through a pressurized swirl pump, a flow control valve and a flow meter and drop as a downward flow, and an ozone contact tank. A coagulant injection device for supplying a coagulant to each lower injection pipe, a flotation sludge collection device installed near the upper wall of each reaction chamber, and a portion of the ozone contact tank facing the bottom wall below. The ozone contact tank is provided with a rapid compression section for adjusting the pressure inside the tube formed in the vicinity of the opening of the tip of the injection tube, and the ozone is agglomerated in the water to be treated sent to the lower injection tube according to claim 6. Supply agent to aggregate suspended particles and bubbles in the water to be treated, Condensation, and aggregation concentrate was floated on the water surface, a control method of an ozone contact tank which is adapted to intermittently or continuously removed by suction.

According to the ozone contact tank of the first aspect, the ozone gas to be treated is mixed with the pressurized swirl pump to form fine bubbles, and becomes highly dissolved ozone water, and the pressure in the pipe becomes a predetermined value by the rapid compression section. The contact efficiency between ozone gas and water to be treated can be improved by contacting the bottom wall of the contact tank with gas-liquid falling while contacting the adjusted lower injection pipe, and efficient ozone treatment is performed in a short time. is there.

According to the branched ozone contact tank and the control method therefor, one of the water to be treated is highly dissolved ozone by mixing with the ozone gas by the pressurized swirl pump 16 and forming fine bubbles. It becomes water, and the other one is characterized by allowing the reaction to proceed in a short time by bypassing the reaction chambers 1a and 1b together with the highly dissolved ozone water without treatment. Further, according to the ozone contact tank and the control method thereof according to claims 5 and 6, by injecting the coagulant into the water to be treated containing the highly suspended matter, the suspended matter can be concentrated and removed by the flotation method. The effect of reducing the injection rate of ozone and the effect of reducing the load on the sand filter basin, the activated carbon filter device, and the like in the subsequent step can be obtained.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Various embodiments of an ozone contact tank and its control method according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing a first embodiment of an ozone contact tank according to the present invention. In this first embodiment, a pressure type downward injection type ozone contact tank is used as a basic structure. Reference numeral 11 denotes an ozone contact tank, and this ozone contact tank 11 is divided into a plurality of stages from the lowermost stage to the upper stage, and block-type contact chambers 11a, 11b, 11 through which water to be treated can flow.
The ozone-treated water 10 is made of a polymer of c, 11d, and 11e, and the ozone-treated water 10 flows out from the treated water tank 12 provided in the uppermost contact tank 11e. Reference numeral 13 denotes an exhaust 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, and a pressurized swirl pump 16 and a variable speed for adjusting the amount of the inflow water are provided at the inflow portion of the treated water 20 to the inflow pipe 15. 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 which is 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 vertical length of the ozone contact tank 11 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.

Ozone contact tank 1 in the first embodiment
The operation and the operating principle of No. 1 operation 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 1
6a mixes them into fine bubbles to form highly dissolved ozone water, the amount of inflow water is adjusted by the variable speed device 17 and is pumped through the inflow pipe 15, and descends while contacting the gas and liquid in the lower injection pipe 21. At this time, the pressure in the pipe is adjusted to 0 to 4.0 (kgf / cm ² ) by the sudden contraction section 22.

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

At the time of the above operation, it is desirable that both the flow velocity and the pressure of the treated water 20 fed 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 treated water 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 which constitute 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 device (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 next to fluorine and is a harmful substance 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.

Since the ozone contact tank 11 of the first embodiment is composed of a polymer of block type contact tanks 11a, 11b, 11c, 11d, 11e divided into a plurality of stages from the bottom to the top. The feature is 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 treated water / 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, there is a correlation between the ozone absorption efficiency, the L / G ratio, and the pipe pressure. If the ozone absorption efficiency is 90% or higher, the L / G ratio is 10 or higher under a constant ozone gas flow rate. Moreover, the pipe pressure is 1.5 (kg
f / cm ² ) or more. Therefore, an operation satisfying both conditions is required, and the flow rate of the water to be treated 20 can be reduced by adjusting the inflow water amount and adjusting the orifice diameter of the rapid contraction unit 22 by controlling the rotation speed by the variable speed gear 17.

Next, a second embodiment of the present invention will be described with reference to FIG. The second embodiment is an example of a device relating to a combination of a vertical bypass type ozone contact tank and a pressure type downward injection type ozone contact tank.

As shown in the figure, the flow path of the water 20 to be treated is the first
Is divided into a flow path 23 and a second flow path 24 of
The flow path 24 is directly connected to the vertical bypass type ozone contact tank 1. Inside the up-and-down bypass ozone contact tank 1, a gas phase portion is separated by a partition wall 2 rising from the bottom surface and a partition wall 3 hanging from the top surface, and a liquid phase portion is communicated with each other. The reaction chambers 1a and 1b of the formula are constructed.

In this ozone contact tank 1, each reaction chamber 1a,
A dissolved ozone concentration meter 31 for measuring the dissolved ozone (DO ₃ ) concentration in 1b and an organic matter concentration meter 32 for measuring the organic matter concentration are additionally provided. The organic substance concentration meter 32 is a measuring device for obtaining the organic substance concentration from the ultraviolet absorbance (UV), and specifically has a function of measuring the UV value derived from the organic substance by removing the dissolved ozone in the water to be treated. There is. The reaction chambers 1a, 1 of the ozone contact tank 1
One of the features is that an ozone gas diffuser having fine holes as in the conventional example (see FIG. 6) is not arranged near the bottom surface in b.

The other first flow path 23 is connected to the flow control valve 2
5, the first vertically arranged in the reaction chamber 1a via the pressurization pressurization vortex pump 16, the flow control valve 26, and the flow meter 29.
Is connected to a lower injection pipe 21a of the first lower injection pipe 21a, and a flow path 27 branched at an upper portion of the first lower injection pipe 21a is vertically arranged in the second reaction chamber 1b via a flow control valve 28. And is connected to the second lower injection pipe 21b. The lower injection pipes 21a, 21b are provided with sharply contracted portions 22, 22 for adjusting the pressure inside the pipes in the vicinity of the tip end openings thereof.

Reference numeral 7 is an ozone generator, 30 is a control unit, and this control unit 30 is composed of a U-tube step feed arithmetic unit 30a and a neuro-fuzzy control unit 30b. The measured values of the densitometer 31 and the organic matter densitometer 32 and the measured value of the flowmeter 29 are input, and the control signal of the control unit 30 is input to the flow control valve 2.
5, 26, 28 and the ozone generator 7.

The operation and control example of the second embodiment will be described below. First, as the flow rate control valves 25, 26 and the pressurizing / pressurizing vortex pump 16 are driven, about 2 to 20% of the water to be treated 20 is allowed to flow into the first flow path 23, and the remaining portions of the water to be treated 98 to 8 are treated.
0% is made to flow into the first flow path 24.

The water 20 to be treated which has flowed into the first flow path 23.
As described in the first embodiment, the ozone gas obtained by the ozone generator 7 is fed into the water to be treated in accordance with the driving of the pressurizing vortex pump 16 arranged in the first flow path, and the ozone gas and the ozone gas The high-dissolved ozone water obtained by mixing the treated water 20 with the impeller portion of the pressurization vortex pump 16 and making it into fine bubbles forms the lower injection pipes 21 a, 21 via the flow meter 29.
It is sent to b and descends while contacting gas and liquid. At this time, the pressure in the pipe is optimally adjusted by the rapid contraction portion 22.

On the other hand, the water to be treated 20 that has flowed into the second flow path 24 proceeds with the highly dissolved ozone water that has flowed out from the lower injection pipes 21a and 21b while bypassing the overflow reaction chambers 1a and 1b. Then, the ozone-treated water 10 flows out from the ozone contact tank 1.

During the above operation, the flow rate of the treated water 20 in the first flow path 23 measured by the flow meter 29 is input to the control unit 30 and the treated water 20 in the ozone contact tank 1 is dissolved. The ozone concentration and the organic substance concentration are measured by the dissolved ozone concentration meter 31 and the organic substance concentration meter 32, respectively, and the measured values are input to the control unit 30 as feedback signals. The flow rate control valves 25, 26, 28 are controlled by the U-tube step feed computing device 30a and the neuro-fuzzy control device 30b that form the control unit 30 so that the flow rate of the water 20 to be treated flowing in the flow path 1 becomes the minimum necessary.
Is calculated, and the ozone injection rate and the L / G ratio are controlled by the drive control of the ozone generator 7. L / G
Is a ratio of specific treated water flow rate / ozone gas flow rate, and is controlled so that this L / G ratio is 10 or more and the internal pressure of the lower injection pipes 21a and 21b is 1.5 (kgf / cm ² ) or more. To be done.

According to the second embodiment, one of the branched water to be treated becomes highly dissolved ozone water by mixing with the ozone gas by the pressurizing vortex pump 16 and formation of fine bubbles, and the other is highly dissolved as untreated. Reaction chambers 1a, 1 with ozone water
By bypassing b, there is an effect of advancing the reaction in a short time, and since there is no ozone diffusion diffuser like in the conventional example in the reaction chambers 1a and 1b, clogging of the diffuser occurs. There is no fear of this, and there is an effect that it is advantageous in terms of maintenance and operating costs.

FIG. 5 is a schematic diagram for explaining a third embodiment of the present invention. This third embodiment is similar to the second embodiment, in which the upper and lower opposed bypass ozone contact tanks and the pressurized downward injection ozone contact are used. This is an example relating to the combination with the tank, and since the basic configuration is the same as that in FIG. 4, the same components are denoted by the same reference numerals.

In the third embodiment, in addition to the structure of the second embodiment, a coagulant injection device 35 is provided in the ozone contact tank 1, and the first lower injection pipe 21a and the second lower injection pipe 2 are provided.
Pipes 36 and 37 for supplying a flocculant to 1b are connected. Further, a floating sludge collecting device 38 is provided near the upper wall of the reaction chambers 1a and 1b. The floating sludge collecting device 38 is provided to collect suspended matter generated in the reaction chambers 1a and 1b and suck and remove it with a vacuum device (not shown).

According to the third embodiment, as in the second embodiment, the flow rate control valves 25 and 26 and the pressurizing / pressurizing vortex pump 16 are used.
2 to 20% of the water to be treated 20 flows into the first flow passage 23 and the remaining 98 to 80% of the water to be treated flows into the first flow passage 24. Water 20 that has flowed into the flow path 24 of the above together with the water 20 that has been sent to the lower injection pipes 21a and 21b is an overflow type reaction chamber 1a, 1b.
The reaction proceeds while bypassing. In parallel with this operation, the coagulant such as polyaluminum chloride filled in the coagulant injection device 35 is supplied to the first lower injection pipe 21a and the second lower injection pipe 21b through the pipes 36 and 37. Then,
The suspended matter and fine bubbles in the water to be treated 20 are aggregated and concentrated by the aggregating agent and float on the water surface. This aggregated concentrate is sucked and removed by intermittent or continuous operation of a vacuum device (not shown). The flow control valve 2 by the control unit 30
The ozone injection rate and the L / G ratio are controlled by the opening degrees of 5, 26, 28 and the drive control of the ozone generator 7 in the same manner as in the second embodiment.

In the illustrated example, the coagulant is supplied from the coagulant injection device 35 to both the first lower injection pipe 21a and the second lower injection pipe 21b.
The coagulant may be supplied only to the reaction chamber 1b on the subsequent stage side.

According to the third embodiment, since the flocculant can be concentrated and removed by the flotation separation method by injecting the coagulant into the water 20 to be treated containing the highly suspended matter, the ozone generator 7 can be used.
It is possible to reduce the injection rate of ozone due to the above, and further, it is possible to obtain the effect that the load on the sand filter, the activated carbon filter, etc., which is the subsequent step of the ozone contact tank 1, is reduced.

[0052]

As described in detail above, according to the ozone contact tank of claim 1 of the present invention, the ozone gas is fed into the water to be treated through the ozone injection pipe and then mixed by the pressurized vortex pump.・ It is made into fine bubbles and becomes highly dissolved ozone water, and after the amount of inflow water is adjusted by the variable speed device, the pressure inside the pipe is adjusted to a predetermined value by the rapid contraction part, and the liquid drops in contact with the lower injection pipe. Since the contact efficiency between the ozone gas and the water to be treated can be improved by hitting the bottom wall of the contact tank, the same treatment characteristics can be obtained with a residence time shorter than the residence time of the conventional diffuser tube type ozone contact tank.

According to the ozone contact tank and the control method thereof according to claims 2 and 3.4, the water to be treated is branched, and one of them is highly dissolved ozone by mixing with ozone gas by a pressurized vortex pump and forming fine bubbles. Water becomes water, and the other one is an unprocessed one, and bypasses the reaction chamber together with highly dissolved ozone water, which has the effect of advancing the reaction in a short time. Further, since there is no diffuser for ozone diffusion in the reaction chamber, clogging of the diffuser due to iron, manganese, etc. does not occur, which is advantageous in terms of maintenance and operating costs. At the beginning of the ozone reaction to the water to be treated, a highly reactive substance is removed by the diffusion efficiency of the lower injection pipe, which promotes the reaction process in the initial stage where the diffusion of ozone gas is rate-determining and In the latter period, the reaction by the ozone contact tank and the retention time are secured to remove low-reactivity substances, and the latter stage reaction in which the ozone reaction is rate-determining is promoted. Especially L / G ratio of 10
By setting the internal pressure to 1.5 (kgf / cm ² ) or more, stable processing characteristics can be obtained.

Further, according to the ozone contact tank and the control method therefor according to claims 5 and 6, in addition to the above effects, the highly turbid component contained in the water to be treated is concentrated and removed by the floating separation method by injecting a coagulant. Therefore, it is possible to obtain the effect of reducing the injection rate of ozone and the effect of reducing the load on the sand filter, the activated carbon filter, and the like, which are the subsequent steps.

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. Especially, there is no problem that the construction work of the facility is complicated unlike the conventional U-tube type ozone reaction tank, and the construction cost can be reduced, and the deposits stored in the reaction tank and the cleaning inside the tank can be performed. Therefore, it is possible to easily carry out the above, and it is possible to immediately take action even if a failure occurs near the bottom of the reaction tank.

[Brief description of drawings]

FIG. 1 is a schematic diagram generally showing a first embodiment of an 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 schematic diagram generally showing a second embodiment of the present invention.

FIG. 5 is a schematic diagram generally showing a third 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]

7 ... Ozone generator 11 ... Ozone contact tank 11a, 11b, 11c, 11d, 11e ... Block type 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 21a ... First lower injection pipe 21b ... Second lower injection pipe 20 ... Covered Treated water 22 ... Rapid reduction section 23 ... First flow path 24 ... Second flow path 25.26, 28 ... Flow control valve 29 ... Flow meter 30 ... Control section 31 ... Dissolved ozone concentration meter 32 ... Organic matter concentration meter 35 Coagulant injection device 38 Floating sludge collection device

Claims (6)

[Claims] 1. A vertical ozone contact tank through which treated water can flow while accumulating, and an ozone gas obtained by an ozone generator which is provided at an inflow portion of the treated water fed into the ozone contact tank. A pressurized vortex flow pump for gas-liquid mixing with treated water, a variable speed regulator for adjusting the inflow amount of the treated water, and an inside of the ozone contact tank are inserted and arranged so that the treated water falls as a downward flow. An ozone contact tank comprising: an injection pipe; and an abruptly reducing portion for adjusting the internal pressure of the pipe, which is formed in the vicinity of the tip opening of the lower injection pipe at a portion facing the bottom wall of the ozone contact tank. 2. An up-and-down bypass ozone contact tank having a plurality of reaction chambers in which a gas phase portion is separated and a liquid phase portion is communicated with each other, and vertically arranged in each reaction chamber. On the bottom wall of the ozone contact tank and the lower injection pipe where the ozone gas obtained by the ozone generator and the water to be treated flow in through the pressurized swirl pump, the flow control valve and the flow meter and fall as a downward flow. An ozone contact tank, characterized in that it comprises an abruptly reducing portion for adjusting the internal pressure of the pipe, which is formed in the vicinity of the opening of the tip of the lower injection pipe at the facing portion. 3. A dissolved ozone concentration meter and an organic matter concentration meter are arranged in each of the reaction chambers, and the control unit controls the flow rate based on the measured values of the dissolved ozone concentration meter and the organic matter concentration meter and the measurement value of the flowmeter. 3. The method for controlling an ozone contact tank according to claim 2, wherein a control for optimally adjusting the ozone injection rate and the L / G ratio is performed by calculating the valve opening degree and the driving condition of the ozone generator. 4. The ratio of the flow rate of water to be treated / the flow rate of ozone gas (L / G ratio) in the lower injection pipe is 10 or more, and the pipe internal pressure is 1.5 (kgf / cm ² ) or more. Control method for ozone contact tank. 5. A vertical bypass type ozone contact tank having a plurality of reaction chambers in which a gas phase portion is separated and a liquid phase portion is communicated with each other, and vertically arranged in each of the reaction chambers. The ozone gas obtained from the ozone generator and the water to be treated are installed in the ozone contact tank and the lower injection pipe through which the ozone gas flows in through the pressurized swirl pump, the flow rate control valve and the flow meter and falls as a downward flow. , A coagulant injection device for supplying a coagulant to each lower injection pipe, a flotation sludge collector installed near the upper wall of each reaction chamber, and a tip of the lower injection pipe at a portion facing the bottom wall of the ozone contact tank An ozone contact tank, comprising: a rapid contraction portion formed in the vicinity of the opening for adjusting the pressure inside the pipe. 6. A coagulant is supplied to the water to be treated sent to the lower injection pipe to aggregate and concentrate turbidity and air bubbles in the water to be treated, and the flocculated concentrate floating on the water surface is intermittently or The method for controlling an ozone contact tank according to claim 5, wherein the suction and removal are performed continuously.