JPH0471687A - Water treating device using ozone and defoaming method thereof - Google Patents

Abstract

PURPOSE:To efficiently remove the foam generated in a contact tank by mounting a water flow control plate to the water treating device having a flow regulating tank and the contact tank 18 and controlling the water flow from the flow regulating tank to the contact tank. CONSTITUTION:The water flow control plate 21 having an inclination with a water surface is mounted slight apart from the water surface near the partition plate 16 in the contact tank 18. The water 2 to be treated flowing into a reaction tank 1 collides against the water flow control plate 21 and flows down along the partition plate 16 to the contact tank 18. On the other hand, the passage rate of the ozonizing air from an air diffusion pipe 11a is decreased and the passage rate of the ozonizing air from an air diffusion pipe 11b is increased, to generate swirling flow in the water 2 to be treated in the contact tank 18. The bubbles 20 accumulating on the water surface are moved to the place of the water flow control plate 21 by this swirling flow and are thereafter withdrawn into the contact tank 18 together with the water 2 to be treated flowing into the spacing between the water flow control plate 21 and the partition plate 16. Then, the stagnation of the bubbles in the space part 16 is obviated.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to relatively large-scale water treatment equipment, such as advanced treatment of water and sewage and factory wastewater treatment, using ozone, and the reaction between water to be treated and ozone. This invention relates to a method for defoaming foam caused by.

[Conventional technology]

Ozone is used as the treated water in water treatment equipment, but in large-scale equipment such as water and sewage treatment, from the viewpoint of reaction engineering, ozone and treated water come into contact with each other in countercurrent flow. A contact type reaction tank is often used.

FIG. 3 is a schematic diagram showing an example of the main part configuration of such a water treatment device. In FIG. 3, treated water 2 is supplied to the reaction tank 1 from a tank 3 by a pump 4 through a treated water volume 5, and is discharged from a treated water outlet 6. On this occasion,
Pressurized air is sent to the ozone generator 8 using the compressor 7, and the generated ozonized air is divided into two routes, for example, passes through flow rate control valves 9a, 9b, flow meters 10a, 10b, and is then sent to the reaction tank l by aeration pipes 11a, llb. Exhaust ozone that does not participate in the reaction that is injected and diffused into the reactor and reacts with the water to be treated 2 exits from the exhaust ozone outlet 12 at the top of the reaction tank l and is transferred to the pipe 13.
, and is led to the treatment tower 14 where it is decomposed into oxygen.

At the same time, a part of the wandering ozone is collected by an ozone concentration measuring device 15 installed in a branch part of the pipe 13.

The inside of the reaction tank 1 is divided by several partition plates 16, and roughly divided into a rectifier tank 17 that rectifies the water to be treated 2 transported by the pump 4 at the inlet, and a rectifier tank 17 that rectifies the water 2 transported by the pump 4 at the inlet, and a rectifier tank 17 that is arranged at equal intervals at the bottom in the subsequent stage. It consists of a contact tank 18 in which fine ozone bubbles are diffused by aeration pipes 11a and 11b. Arrows indicate the direction of water flow.

When water treatment is carried out using such a device, when treating water 2 with foaming properties, foams and solids rise to the surface of the water due to the reaction with ozone, and these are mixed between the water surface and the inside of the reaction tank 1. FIG. 4 is a schematic diagram showing this situation, and is accumulated in the space 19 formed between the upper wall and the upper wall.
Only a portion of the reaction tank 1 and the ozone supply system are shown slightly enlarged.

In the treated water 2 having foaming properties as shown in FIG. 4, bubbles 20 stay on the water surface. In this state, it becomes difficult for exhaust ozone to flow through the pipe 13, and the water level fluctuates and the amount of ozone injected decreases due to changes in the internal pressure of the reaction tank 1. Furthermore, the bubbles reach the treatment tower 14 and the ozone concentration measuring device 15, causing a decrease in their performance or failure. To deal with this, conventional defoaming measures include spraying water, air, etc., mechanical, thermal methods, and other methods such as using defoaming agents.

[Problem to be solved by the invention]

However, all of the antifoaming measures described above lack decisive effects, and in particular, there has been little experience so far in water treatment, and furthermore, they have the following limitations.

(2) When air is sent, the load on the exhaust ozone treatment tower 14 increases.

■Since it is a water supply, the water supply cannot be stopped once it has been applied, and mechanical and thermal defoaming devices with complicated structures cannot be used.

■ Chemicals such as antifoaming agents cannot be used in water supplies.

■The degree of foaming varies depending on the season, and it may not foam at all except during the winter dry season, which poses storage management problems.

The present invention has been made in view of the above points, and its object is to provide an apparatus and method for efficiently removing foam generated in an ozone water treatment apparatus and retained in a contact tank.

[Means to solve the problem]

In order to solve the above problem, we installed a water flow control plate that maintains a small gap with the water surface and is inclined with respect to the water surface near the contact tank side of the partition plate that separates the rectification tank and contact tank of the water treatment equipment. This structure uses two series of aeration pipes, one with a small aeration volume and one with a large aeration volume, to create a swirling flow in the water to be treated in the contact tank. The bubbles are moved by the current to the position of the water flow control plate, and when the water to be treated flows from the rectifier tank with a high water level to the contact tank with a low water level, the bubbles are dropped into the contact tank along the water flow control plate. be.

[Effect]

With the above equipment configuration and defoaming method, when the bubbles generated in the contact tank rise to the surface of the water, they are successively swept away in the direction of the water flow control board by the swirling flow of the water to be treated, and also flow from the rectifier tank. Since the bubbles are dragged into the contact tank by the water flow that collides with the water flow control plate, bubbles do not always remain in the space inside the reaction tank.

〔Example〕

Hereinafter, the present invention will be explained based on examples.

FIG. 1 is a schematic diagram showing the main structure of a water treatment apparatus to which the present invention is applied, and parts common to those in FIG. 3 are represented by the same symbols. The difference between FIG. 1 and FIG. 3 is that a water flow control plate 21 is attached to the reaction tank 1 near the partition plate 16 in the contact tank 18, slightly away from the water surface and inclined to the water surface. . The rest of the configuration is the same as that in FIG. 3, so a description thereof will be omitted.

FIG. 2 is a schematic diagram showing only a part of the reaction tank 1 and ozone supply system of the apparatus of FIG. 1 having a water flow control plate 21,
It corresponds to FIG. 4 for comparison.

In FIG. 2, the water level in the rectifier tank 17 is higher than that in the contact tank 18 due to the partition plate 16 between the rectifier tank 17 and the contact tank 18. flows into the contact tank 18 through the rectifier tank 17, but at this time, the water to be treated 2 collides with the water flow control plate 12, so that it flows down into the contact tank 18 along the partition plate 16. Therefore, the flow rate control valve 9a is throttled down.
The ventilation amount of ozonized air from the aeration pipe 11a is reduced,
Further, by opening the flow rate control valve 9b and increasing the amount of ozonized air flowing from the aeration pipe 11b, the contact tank 18
A swirling flow as shown by the arrow is generated in the water to be treated 2 inside.

Comparing the state of the bubbles when doing this with Figure 4, we find that
The bubbles 20 accumulated on the water surface in FIG. 4 are moved from this position to the position shown in FIG. 2, that is, the water flow control plate 21, by the swirling flow in the contact tank 18. Here, the bubbles 20 are dragged into the contact tank 18 together with the water to be treated 2 flowing into the gap between the water flow control plate 21 and the partition plate 16, so that the bubbles do not stay in the space 19. In this way, the exhausted ozone can be sent to the pipe 13 without any hindrance, and other inconvenient situations related to the generation of bubbles are eliminated.

〔Effect of the invention〕

Conventionally, there was no effective means for removing bubbles generated in the reaction tank when a large-scale reaction tank was used for water treatment, such as water treatment, by aerating ozone into the tank. As mentioned, venting ozonated air into the contact tank2
A sloping system that creates a swirling flow in the water to be treated by changing the airflow rate of the air diffuser pipe in the system, removes the bubbles that float to the surface of the water and accumulate there, and drops the water into the rectifier tank and the contact tank with a water level difference. Since the bubbles are collected at the water flow control plate position and drawn into the contact tank along the water flow control plate, the bubbles do not remain on the water surface during the water treatment process, and various types of bubbles caused by the generation of bubbles are eliminated. By eliminating these inconveniences and simply installing a water flow control plate and operating a simple valve when venting ozonated air into the contact tank, extremely effective defoaming can be achieved with easy maintenance.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the main part configuration of the water treatment equipment of the present invention, Fig. 2 is a schematic diagram showing a part of the reaction tank and ozone supply system of the equipment of the present invention, and Fig. 3 4 is a schematic diagram showing the main part configuration of a conventional water treatment device, and FIG. 4 is a schematic diagram showing a part of the reaction tank and ozone supply system of the conventional water treatment device. 1: Reaction tank, 2: Water to be treated, 3: Tank, 4: Pump,
5: Treated water inlet, 6: Treated water outlet, 7: Compressor, 8 Niosin generator, 9a, 9b: Flow rate control valve, 1
0a, 10b: flow needle, 11a, 11b: diffuser pipe, 12: exhaust ozone outlet, 13: piping, 14: treatment tower, 1
5 Niosin concentration measuring device, 16: Partition plate, 17: Rectifier tank, 18: Contact tank, 19: Space, 20: Foam, 21: Water flow diagram 2 lA3 fertilizer diagram 4

Claims (1)

[Claims] 1) Ozonated air is injected into the reaction tank from an aeration pipe arranged at the bottom of the contact tank of a reaction tank having a high water level rectifying tank and a low water level contact tank separated by a partition plate. The contact tank area near the partition plate of the apparatus for treating wastewater flowing therein has an inclination such that the water to be treated flowing from the rectifying tank collides and flows into the contact tank, and the water surface of the contact tank A water treatment device that uses ozone and is characterized by being equipped with a water flow control plate that maintains gaps. 2) In removing bubbles generated in the water treatment apparatus according to claim 1), two series of aeration pipes are arranged, and the amount of ozonized air is made small in one direction and large in the other, so that the amount of ozonized air to be treated in the contact tank is Water using ozone, characterized in that a swirling flow is generated in water, and bubbles floating and staying on the water surface of the contact tank are moved to a position of a water flow control plate and drawn into the contact tank by the swirling flow. Defoaming method for processing equipment.