JPH09168778A - Floatation purifying apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate a large amt. of fine air bubbles by dissolving air even in sewage in which air (oxygen) is hardly dissolved with high efficiency. SOLUTION: In a floatation purifying apparatus wherein compressed air is supplied to a pressurizing tank 4 to dissolve air in water while this water is opened to the atmosphere to convert dissolved air to fine air bubbles and a pollutant in water is taken out along with air bubbles, a vacuum degassing means 2 depressurizing water before pressurization to degass the air dissolved in water is formed to the pressurizing tank or on the upstream side thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention dissolves oxygen in water by, for example, pressurizing and dissolving air in wastewater, then releasing the wastewater to the atmosphere, and taking out the dissolved air as fine bubbles. The present invention relates to a pressurized flotation purification device that floats and separates dirt in water together with the bubbles.

[0002]

2. Description of the Related Art When water is treated, a pressure floating purification method is generally known in which a large amount of fine bubbles are generated in the water to be treated, and the fine bubbles are brought into contact with water for floating separation. As a device for performing the pressure levitation purification, the pumped water is put into a closed tank, and a high pressure (3
This air is melted into water by supplying pressurized air (~ 5 kg / cm ² ), while the water in which this air is dissolved is released into the atmosphere to make the dissolved air into fine bubbles, thereby removing dirt in the water. What is taken out together with the fine bubbles is well known.

[0003]

By the way, although the above-mentioned pressurized flotation purification device is generally used for factory drainage,
It is limited to pretreatment. This is because the procedure by the pressurized flotation purification device is performed in the process of mixing flocculant and water → flock generation → floating separation by fine bubbles.

That is, the problem here is the agglomeration, and generally, it is said that the agglomerates that can be agglomerated are particles having a diameter of 1 μm or more. It can hardly be removed by the levitation purifier.

The present invention addresses the above situation and removes the dissolved gas by degassing by depressurizing the water to be treated before pressurizing it, and by removing this gas, the next step The purpose is to increase the dissolution rate of the pressurized air.

[0006]

That is, the feature of the pressurized flotation purification device of the present invention which meets the above-mentioned object is that water pumped up by a pressure pump or the like is put in a pressure tank and pressurized air is stored in the tank. Is supplied to the air to dissolve the air into the water, and by releasing the water to the atmosphere, the dissolved air is formed into fine bubbles, and the water in the pressurized flotation purifying device takes out the dirt from the water together with the bubbles. At the upstream side including the tank, there is provided a vacuum degassing means for depressurizing the pumped water and degassing the gas previously dissolved in the water.

Further, in the above-mentioned purification apparatus of the present invention, the decompression deaeration means is constituted by a decompression tank installed upstream of the pressurization tank and a vacuum pump connected to this tank. It is also preferable to carry out the depressurization by the depressurization degassing means within a vacuum range of 200 to 700 mmHg.

The pressurizing tank is formed in an upright cylindrical shape, and water is jetted to the upper part of the outer peripheral portion of the pressurizing tank from above the liquid surface in the tangential direction of the tank, and the jetted water causes It is also possible to form a nozzle portion that generates a vortex in the tank.

[0009]

In the above-mentioned pressurized flotation purifying apparatus of the present invention, it is possible to remove gas and odor dissolved in water, including extra gas in water, by decompression. Since it can be done in the previous step of air pressurization, it increases the dissolution rate of air in the above air pressurization step, increases the amount of fine bubbles at the time of opening to the atmosphere, and supplies oxygen to wastewater with high efficiency. Is possible.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram showing a pressurized flotation purification apparatus according to an embodiment of the present invention. In the figure, 1 is a pool of water before treatment, 2 is a depressurizing tank, 3 is a pressurizing pump, 4 is a pressurizing tank, 5 Indicates a pool of water after treatment, and S indicates a control panel.

The depressurizing tank 2 is provided with a vacuum pump 6 for depressurizing the water in the tank 2 and degassing a gas previously dissolved in the water, a depressurization adjusting valve 7, a flow meter 8, and a pressure. A sensor 9 and a water level sensor 10 are provided.

The decompression adjusting valve 7 adjusts the degree of vacuum in the decompression tank 2 to adjust the amount of gas removed in the tank 2 and the overall flow rate. In addition, the above vacuum pump 6
By discharging the gas accumulated in the upper portion of the tank 2, it is possible to remove the gas having a higher dissolution rate than air (oxygen) from the water, and to increase the dissolution rate of air in the next step. The water level sensor 10 controls ON / OFF of the vacuum pump 6, and the pressure sensor 9 measures the degree of vacuum in the tank 2 and detects an abnormal pressure.

On the other hand, the pressurizing tank 3 is provided with a nozzle portion 11 formed at a water outlet continuing from the pressurizing pump 3, an air compressor 12, a pressure sensor 13, and a water level sensor 14. In addition, this pressurizing tank 4
A pressure release valve 15 for discharging the pressurized water to the pool 5 and an automatic drain valve 16 for discharging the drain are provided in the lower part of the.

The nozzle portion 11 is installed in the vicinity of the outer peripheral portion of the pressurizing tank 4 which is provided in a cylindrical shape, and jets water from above the liquid surface to diagonally below the tangential direction of the tank 4, and the jetted water This causes a swirl in the water in the tank 4. Water is the injection is pressurized to 3kg / cm ² ~5kg / cm ² by the pressure pump 3.

In the pressurizing tank 4, three agitating plates 17 are radially fixed to the outer peripheral portion of the tank 4 so as to be orthogonal to the swirl flow. The stirring effect is enhanced. Furthermore, a rod-shaped permanent magnet 18 is installed at the center of the pressurizing tank 4 with the upper pole as the N pole and the lower pole as the S pole. That is, by rotating the water sprayed from the nozzle portion 11 in the tank 4 around the magnet 18, the water and the air are more easily dissolved by the influence of the magnetic field.

At the nozzle portion 11 and the stirring plate 17, the air in the upper portion of the tank 4 is injected from the nozzle portion 11 so as to generate a vortex in the tank 4, and the vortex is mixed by the stirring plate 17. That is, the vortex and the stirring plate 1
When used in combination with No. 7, it is possible to efficiently mix and dissolve air and water without requiring any other power.

The air compressor 12 is for sending pressurized air into the pressurizing tank 4, and the water level sensor 14 detects the water level to detect the water level.
2 ON / OFF control is performed. And the pressure sensor 1
3 measures the pressure to detect the presence or absence of abnormal pressure, and the automatic drain valve 16 periodically drains water to prevent foreign matter from adhering to the pressurizing tank 4 and to discharge dust and the like. Have

Further, the pressure release valve 15 is provided for the pressurized water in which air is dissolved in a high concentration from the pressurizing tank 4 to the pool 5.
By opening to the above, fine bubbles are generated in the pool 5 from the pressurized water having a large amount of dissolved oxygen.

Finally, the control panel S uses a timer to pressurize the pump 3, vacuum pump 6, air compressor 12,
And the automatic operation and ON / OFF control of the automatic drain valve 16 are performed. The pressure sensors 9 and 13 are connected to the tanks 2 and
When the abnormal pressures are detected in 4 respectively, the operation of the entire apparatus is automatically stopped.

In the pressurized flotation purifying apparatus of the above-described embodiment of the present invention, first, the depressurizing tank 2 has a pressure of 200 to 70.
The gas dissolved in water is removed by degassing under reduced pressure at a vacuum degree of 0 mmHg. It is thought that the gas molecules are in the gaps between the water molecules, but under the conventional pressure / aeration, the dissolved gas molecules are pushed out first and oxygen etc. are inserted into these gaps. Is inefficient. For example, in the ratio of dissolving in water, assuming that oxygen is 1, ammonia is 3000.

Next, the degassed water is pressurized and mixed with air. In this case, since the gas easily dissolves in the liquid under pressure according to Henry's law, it is possible to increase the amount of dissolved oxygen in water at a highly efficient rate in the process of deaeration to pressurization. In this case, the amount of dissolved oxygen in the water can be increased more efficiently by mixing water and air in the pressurizing tank 4 by the vortex flow of the nozzle portion 11. By the way, if the efficiency of air dissolution increases due to degassing, the pressure tank 4
While the residence time of water inside is 1.5 to 2 minutes, the time can be shortened and the pressure tank 4 can be downsized. The applied pressure is usually said to be 3 to 5 kg / cm ² , but it is possible to lower the applied pressure.
In the above process, the air compressor 12 is turned on / off by detecting the water level in the pressurizing tank 4.
If the FF is performed, it is not necessary to adjust the amount of air dissolved, and the pressure can be arbitrarily set within the capacity of the pressurizing pump 3 without being affected by the pressure adjustment by opening and closing the open valve. Then, the pressure release valve 15 of the pressurizing tank 4
By opening and opening the pressurized water to the pool 5, a large amount of fine air bubbles are generated in the water, and the dirt can be removed from the water by floating and separating the dirt as the air bubbles float.

Although the embodiment of the present invention has been described above, the depressurizing tank 2 can be configured to be used also as the pressurizing tank 4 instead of being provided independently as in the embodiment. It is also preferable to attach a deodorizer 19 for deodorizing the degassed gas to the depressurizing tank 2 and attach a check valve 20 to the duct of the pool 1 if necessary.

[0023]

As described above, the pressurized flotation purifying apparatus of the present invention is a decompressor for depressurizing pumped water and degassing gas dissolved in water upstream of a tank for pressurizing air. Degassing means is formed, and in addition to the excess gas in water, the gas and odor dissolved in water are removed by the above decompression, and this decompression and deaeration must be performed in the pre-process of pressure dissolution. This increases the dissolution rate of air by the amount of excess gas removed, thereby efficiently supplying oxygen to the wastewater, increasing the amount of fine bubbles when opening to the atmosphere, and improving the collection rate of dirt. As a result, the remarkable effect of providing a water treatment plant which is smaller in scale and lower in cost than the conventional system is achieved. Further, the pressurizing tank is formed on an upright cylinder, and water is jetted in the tangential direction of the tank from above the liquid level to the upper part of the outer peripheral portion of the pressurizing tank, and the jetted water enters the tank. By forming the nozzle portion that generates the vortex, it becomes possible to further increase the mixing ratio of water and air and to further improve the dissolution ratio of the pressurized air.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a pressurized levitation purification apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 1 pool 2 depressurizing tank 3 pressurizing pump 4 pressurizing tank 5 pool 6 vacuum pump 7 decompression adjusting valve 8 flow meter 9 pressure sensor 10 water level sensor 11 nozzle 12 air compressor 13 pressure sensor 14 water level sensor 15 pressure release valve 16 automatic Drain valve 17 Stirrer plate 18 Permanent magnet 19 Deodorizer 20 Check valve

Claims (4)

[Claims] 1. The water pumped up by a pressure pump or the like is placed in a pressurizing tank, and pressurized air is supplied into the tank to dissolve the air into the water, while releasing the water to the atmosphere. In a pressurized flotation purification device that forms dissolved air as fine bubbles and takes out dirt in water together with the bubbles, on the upstream side including the pressurizing tank,
A pressurized flotation purification device comprising a reduced pressure deaeration means for reducing the pressure of the pumped water and degassing a gas previously dissolved in the water. 2. The pressurized levitation purification apparatus according to claim 1, wherein the decompression deaeration means comprises a decompression tank installed upstream of the pressurization tank and a vacuum pump connected to the tank. 3. The reduced pressure by the reduced pressure deaeration means is 200 to
The pressurized floating purification apparatus according to claim 1 or 2, which is operated in a vacuum degree range of 700 mmHg. 4. The pressurizing tank is formed in an upright cylindrical shape, and water is jetted to the upper part of the outer peripheral portion of the pressurizing tank from above the liquid surface in the tangential direction of the tank, and the jetted water is used to The pressurized flotation purification device according to claim 1, 2 or 3, wherein a nozzle portion for generating a vortex is formed in the tank.