JPH08229579A - Two-vessel type ozone contact vessel apparatus - Google Patents

Abstract

PURPOSE: To make it possible to subject the pollutant in water to be treated to an efficient ozone treatment with a sufficient removal effect. CONSTITUTION: The water which is to be treated and is supplied from an original water inflow pipe 3 and the ozonized air supplied from an ozonized air blow pipe 4 fall in the form of the descending flow of gas-liquid two-phase flow in an inside pipe 2 and are ejected out of the opening of the inside pipe 2. The air bubbles (ozonized air) formed at this time are made into fine bubbles, which are dissolved with high efficiency into the water to be treated. Further, the water to be treated and the ozonised air ascend on the primary reaction vessel 1 side and the fine air bubbles aerate the water to be treated during this time, by which the dissolution of the ozone is progressed and a gas-liquid contact reaction is induced. The water to be treated and the ozonized air, then, pass a treated water introducing pipe 5 and flows out to an ozone contact reaction vessel 10. At this time, the ozonized air is sufficiently dissolved in the water to be treated and, therefore, the gas-liquid contact reaction is accelerated in the ozone contact reaction vessel 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology for treating, disposing and purifying pollutants from wastewater such as advanced tap water treatment, sewage and night soil, and more specifically, dissolving ozone in water to be treated to remove pollutants. Related to the device.

[0002]

2. Description of the Related Art Conventionally, for the purpose of sterilizing tap water, deodorizing and decolorizing in treating waste water, oxidizing treatment of organic substances, etc., a method of dissolving ozone in treated water and treating it has been carried out. As one of the devices for performing ozone treatment, there is a double tube ozone contact device. FIG. 2 shows a double-tube ozone contactor. In FIG. 2, 1 is an outer cylinder pipe, 2 is an inner cylinder pipe, 3 is a raw water inflow pipe, 4 is an ozonized air blowing pipe, 6 is an exhaust ozone taking-out pipe, and 8 is a treated water taking-out pipe. In FIG. 2, the ozonized air press-fitted from the upper part of the inner tube 2 forms bubbles at the confluence of the raw water inlets. The formed bubbles descend in the inner tube 2 together with the water flow, and are destroyed by the shearing force of the water flow, and become fine bubbles to dissolve ozone into the liquid phase. Next, the flow reaching the bottom of the inner cylindrical tube 2 rises on the outer cylindrical tube 1 side, and ozone dissolved in the liquid phase reacts with the pollutants in the liquid phase to remove the pollutants. Further, the exhaust ozone in the gas phase is exhausted from the exhaust ozone extraction pipe 6.

In this case, the dissolution efficiency of ozone in the water to be treated is high due to the mixing accompanied by the atomization and the aeration of the atomized air in the outer tube. However, the processing ability was low for some of the chemicals and difficult-to-react substances such as organic compounds having no unsaturated bond.

[0004]

In such a case, it is necessary to increase the volume of the outer tube in order to increase the treatment capacity and lengthen the contact reaction time with ozone. For that purpose, it is necessary to increase the length of the outer tube or increase the inner diameter of the outer tube. When the length of the outer pipe is increased, the inlet of the raw water inflow pipe is usually located near the surface of the ground in order to reduce the head of water, and the ozone contact tank is buried underground. The burial length increases, and the excavation cost, that is, the construction cost increases. When the inner diameter of the outer tube is increased, a short-circuit flow occurs and the contact efficiency with ozone decreases.

The present invention has been made to solve the above problems, and provides a two-tank type ozone contact tank apparatus capable of surely removing hardly reactive substances and improving the removal efficiency by ozone. The purpose is to do.

[0006]

Means for Solving the Problems As a result of intensive research to solve the problems, in a double-tube ozone contactor, the cross-sectional area of the reaction tank is 100 times or less that of the inner tubular tube,
Furthermore, the treated water after treatment with the double tube ozone contactor is
The present invention has been completed by finding that ozone treatment can be efficiently performed by taking a theoretical residence time of 0 minutes or more.

That is, the two-tank type ozone contact tank apparatus of the present invention comprises a double tube type ozone dissolution tank and an ozone contact reaction tank. The double-tube type ozone dissolution tank is provided in communication with the first reaction tank having a bottom, an inner tube hanging in the first reaction tank and opening near the bottom of the first reaction tank, and the inner tube. The raw water inflow pipe and the ozonized air blowing pipe provided so as to communicate with the upper portion of the inner pipe are provided, and the cross-sectional area of the first reaction tank is 100 times or less the cross-sectional area of the inner pipe. The ozone contact reaction tank connects the second reaction tank in which the theoretical retention time of the treated water is 10 minutes or more, the vicinity of the upper end of the first reaction tank of the double-tube ozone dissolution tank and the vicinity of the upper end of the second reaction tank. And a treated water outlet pipe provided in communication with the second reaction tank.

It is also possible to install a guide plate in the ozone contact reaction tank, and by providing the guide plate, a short circuit flow can be prevented.

In the present invention, the pollutants are pollutants and pollutants to be subjected to deodorization, decolorization, sterilization and oxidation in wastewater, which are substances to be removed in terms of environmental protection, such as trihalomethane-forming ability and pesticides. , Soluble organic substances and the like.

[0010]

In order to carry out the ozone treatment efficiently, it is necessary that the ozone is sufficiently dissolved in the liquid phase and the contact reaction is sufficient.
With the above-described configuration, similarly to the prior art, the treated water supplied from the raw water inflow pipe and the ozonized air supplied from the ozonized air blowing pipe become the downward flow of the gas-liquid two-phase flow and descend the inner pipe, Eject from the opening of the inner tube. The bubbles (ozonized air) formed at this time become fine bubbles and dissolve in the water to be treated with high efficiency. The depth of the double tube type ozone dissolution tank is about 15
Since it is m, the water pressure becomes high at the bottom, the dissolution rate of ozone in the liquid phase in the inner tube is fast, and the dissolution efficiency is 90% or more.

Further, the water to be treated and the ozonized air ascend on the side of the first reaction tank, while the fine bubbles aerate the water to be treated,
Dissolution of ozone progresses and a gas-liquid contact reaction occurs. The cross-sectional area of the first reaction tank is 100 times or less the cross-sectional area of the inner tube. 10
When it is 0 times or more, a short-circuit flow occurs in the first reaction tank section (upflow section), the ozone contact efficiency is lowered, and the reaction efficiency is lowered. Then, the water to be treated and the ozonized air pass through the treated water introducing pipe and flow out to the ozone contact reaction tank. At this time, the ozonized air is sufficiently dissolved in the water to be treated, so that the gas-liquid contact reaction is promoted in the second reaction tank, and the removal rate is improved by carrying out the contact reaction in the ozone contact reaction tank provided separately. .

[0012]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an ozone contact reactor which is an embodiment of the present invention. In FIG. 1, the numbers 3, 4, 6, 8 attached to the drawing are the same as the numbers attached in FIG. In addition, 1 is a first reaction tank, 2 is an inner tube, 5 is a treated water introduction tube, 7 is a double tube ozone dissolution tank, 9 is a guide plate, and 10 is an ozone contact reaction tank. In this embodiment, an outer tube is used as the first reaction tank, an inner tube is used as the inner tube, and the first reaction tank is called an outer tube and the inner tube is called an inner tube. FIG.
In, the outer tube 1 and the inner tube 2 are provided substantially concentrically. The ozonized air press-fitted from the upper part of the inner tube 2 forms bubbles at the confluence of the raw water inlets. The formed bubbles are destroyed by the shearing force of the water flow while descending in the inner cylindrical tube 2 together with the water flow, and become fine bubbles to dissolve ozone in the liquid phase. Next, the flow reaching the bottom of the inner cylindrical tube 2 rises on the outer cylindrical tube 1 side, and ozone dissolved in the liquid phase contacts and reacts with contaminants in the liquid phase. Further, vapor-phase exhaust ozone that has not been used for the reaction is guided to the exhaust ozone extraction pipe 6, where the ozone is decomposed and rendered harmless, and then exhausted to the atmosphere. The treated water treated in the double-tube ozone dissolving tank 7 flows into the treated water introducing pipe 5. The treated water introduction pipe 5 is directly connected to the ozone contact reaction tank 10 which is the next step, and the treated water flows into the ozone contact reaction tank 10 through the treated water introduction pipe 5. A guide plate 9 is provided in the ozone contact reaction tank 10. After passing through the ozone contact reaction tank 10, the treated water is discharged from the treated water extraction pipe 8. As the ozone air to be supplied, it is also possible to reuse the exhaust ozone discharged from the exhaust gas extraction pipe 6.

Based on the above, an experiment was conducted in a water purification plant using a pollutant (mainly an agricultural chemical) which requires a catalytic decomposition time with ozone of 20 minutes or more, and a contact reaction time of 10 minutes or more in an ozone contact tank. The removal rate was 80% or more. Note that simazine, which is a kind of pesticide, was used as the target of the removal rate.

(Comparative Example) An experiment was conducted using the apparatus shown in FIG. The experimental conditions and the like are all the same as in the example. The removal rate was 50% or less. In the double-tube type ozone dissolution tank, the contact time between ozone dissolved in the liquid phase and contaminants is 10 at maximum.
Since it was less than a minute, the contact reaction was not sufficiently carried out and the removal rate was low.

The present invention can be applied to not only the treatment of tap water, sewage and waste water but also treatment of factory waste water, special waste water and the like.

[0016]

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to surely remove even difficult-to-react substances that could not be sufficiently removed by the conventional double-tube type ozone dissolution tank due to lack of contact reaction time, etc. Ozone treatment of pollutants in water can be performed efficiently and with a sufficient removal effect. Further, as the ozone contact reaction tank, a part of an existing settling tank, a diffuser type ozone contact reaction tank or the like can be used, which is economical. Even when a new ozone contact reaction tank is installed, the construction cost can be kept low by simply adding a simple and inexpensive configuration without the need to dig and install a deep water depth of 5 m or less.

[Brief description of drawings]

FIG. 1 is a diagram showing an ozone contact reactor according to an embodiment of the present invention.

FIG. 2 is a view showing a conventional double-tube type ozone contact reaction tank.

[Explanation of symbols]

 1 First reaction tank 2 Inner pipe 3 Raw water inflow pipe 4 Ozonized air blowing pipe 5 Treated water introduction pipe 6 Discharged ozone removal pipe 7 Double pipe ozone dissolution tank 8 Treated water removal pipe 9 Guide plate 10 Ozone contact reaction tank

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeshi Tsuji 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Haruhi Yokota 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Nippon Steel Tube Co., Ltd. (72) Inventor Junji Tada 1-2 1-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Tube Co., Ltd.

Claims (2)

[Claims] 1. A) a bottomed first reaction tank, an inner pipe hanging in the first reaction tank and opening near the bottom of the first reaction tank, and provided in communication with the inner pipe. A double-tube ozone system comprising a raw water inflow pipe and an ozonized air blowing pipe provided in communication with the upper portion of the inner pipe, and the cross-sectional area of the first reaction tank is 100 times or less the cross-sectional area of the inner pipe. (B) Dissolution tank and (b) The second reaction tank having a theoretical residence time of 10 minutes or more, the upper end of the first reaction tank of the double-tube ozone dissolution tank and the upper end of the second reaction tank are connected to each other. A two-tank type ozone contact tank apparatus comprising an ozone contact reaction tank provided with a treated water introduction pipe and a treated water take-out pipe provided in communication with the second reaction tank. 2. A two-tank type ozone contact tank apparatus, wherein the ozone contact reaction tank according to claim 1 is provided with a guide plate.