JP2002059189A - Aeration method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aeration method and device which greatly improves the atomization of air bubbles in order to increase the gas-liquid contact area in an aeration tank and gas stagnation time in aeration of oxygen and ozone, such as water treatment, reduces electric power consumption and eliminates a hindrance, such as clogging. SOLUTION: In the method of releasing the high-density dissolved gas made by dissolving high-pressure gas (oxygen or ozone) within a tank to the aeration tank, the device connects a plurality of tanks through automatic valves to a high-pressure gas supplying device, a raw water circulating pump and the aeration tank as shown in Figure 1 and alternately switches the supply of the high-pressure gas and the supply of the raw water to the tanks by the command of a timer, etc., thereby releasing the high-density dissolved gas water in the tank into the aeration tank.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and apparatus for aerating gas (oxygen or ozone) in water treatment or the like.

[0002]

2. Description of the Related Art In water treatment, aeration with oxygen or ozone has recently been performed in order to prevent formation of harmful organochlorine compounds. However, it is necessary to increase the aeration efficiency of expensive gas. It is important to make the air bubbles finer in order to increase the air bubble residence time. Conventionally, a method of supplying fine gas (oxygen or ozone) from the bottom of the aeration tank through a porous diffuser plate has been adopted. However, the fineness of bubbles is not sufficient, and the fineness of the diffuser plate is also small. Holes are easily clogged,
There was such a problem.

[0003] In particular, in the case of medium- or small-scale oxygen aeration, an oxygen pressure of at least about 5 to 7 atm can be used because an oxygen cylinder or liquid oxygen is usually used as an oxygen source. It is only used for gas extrusion from a gas plate, and wastes energy.

[0004]

In view of the above, the present invention provides
An aeration method and apparatus capable of significantly improving the fineness of bubbles to increase the gas-liquid contact area and gas residence time in an aeration tank, and performing aeration with little power consumption without trouble such as clogging. The purpose is to provide.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, a high-pressure gas (oxygen or ozone) is dissolved in raw water in a tank to produce a high-concentration dissolved gas water. After that, the tank is communicated with the aeration tank to reduce the tank internal pressure to the aeration tank pressure and then supply raw water into the tank, thereby discharging high-concentration dissolved gas water in the tank into the aeration tank. It is an aeration method.

According to a second aspect of the present invention, a plurality of tanks are connected to a high-pressure gas (oxygen or ozone) through an automatic valve.
By connecting to the supply device, raw water circulation pump and aeration tank, and switching between high pressure gas supply to the tank and raw water supply alternately by the timer or the command of the dissolved gas concentration detector in the tank, high concentration in the tank This is an aeration apparatus characterized by discharging dissolved gas water into an aeration tank.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the explanatory diagram of the embodiment shown in FIG.

As shown in FIG. 1, a plurality (two in the illustrated example)
) Tank 1, 1 ′ includes a high-pressure gas supply device 2, a raw water circulation pump 3 and an aeration tank 4, and a gas automatic valve 5,
5 ′, connected via automatic water supply valves 6, 6 ′ and automatic discharge valves 7, 7 ′, and at the outlet of the raw water circulation pump 3, a check valve 8,
A discharge pipe 9 is connected to the automatic discharge valves 7, 7 '. In the figure, 10 is the bottom of the aeration tank, 11 is the water surface of the aeration tank, and 12 is the high concentration dissolved gas water released.

The operation method of the above configuration will be described below. In FIG. 1, each of the black colored automatic valves 5 ', 6' and 7 'shows a closed state, and the high-pressure gas supply device 2 communicates with the tank 1' via the automatic gas valve 5, and the high-pressure gas (oxygen or ozone) Is being dissolved in the raw water in the tank 1 '. On the other hand, for the tank 1 already saturated with gas, the automatic gas valve 5 '
Is closed and the automatic water supply valve 6 and the automatic discharge valve 7 are opened, whereby the high-concentration dissolved gas water is discharged into the aeration tank 4 by the gas pressure through the discharge pipe 9. There is no danger of backflow to the 3 side, and when the pressure of the tank 1 falls below the discharge pressure of the raw water circulation pump 3, the raw water is automatically supplied to the tank 1, so that the high concentration dissolved gas water inside the tank together with the raw water Is released through the discharge pipe 9 toward the aeration tank bottom 10 as indicated by 12 and diffuses into the aeration tank 4. By automatically operating the opening and closing operation of each automatic valve according to a timer or a command from a dissolved gas concentration detector (not shown) in the tank, the supply of the high-pressure gas to the tanks 1 and 1 ′ and the supply of the raw water can be performed. By switching alternately, a continuous aeration operation becomes possible.

[0010] In the case of medium- or small-scale oxygen aeration, a pressure of 5 to 7 atm can be used because an oxygen cylinder or liquid oxygen is used as an oxygen source, but this pressure is conventionally obtained from a porous diffuser plate in an aeration tank. However, in this method, the high pressure of the oxygen source is reduced according to Henry's law (the amount of gas dissolved in water is proportional to the gas pressure). Can be used effectively. In other words, part of the dissolved oxygen becomes microbubbles as the pressure drops, and the remaining part diffuses into the aeration tank while the dissolved oxygen water remains as it is. The area and the bubble residence time can be increased, and high aeration efficiency can be obtained.

In the case of ozone gas aeration, the gas needs to be slightly pressurized. However, since the gas cost is high, the cost required for gas pressurization can be sufficiently compensated. Since the discharge pressure of the raw water circulation pump in the present method is independent of the pressure of the high-pressure gas and depends only on the pipe resistance, no high-pressure pump is required and the power consumption of the pump is small.

[0012]

Since the present invention is configured as described above, it has the following effects.

At the time of aeration of oxygen or ozone gas in water treatment or the like, it is possible to reduce the bubble particle size in the aeration tank and to greatly increase the gas-liquid contact area and the bubble residence time with a small power consumption, so that expensive gas is used. Aeration efficiency can be increased. Further, there is no clogging trouble of the fine holes unlike the conventional diffuser plate method.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention.

[Explanation of symbols]

 1, 1 'tank 2 high-pressure gas supply device 3 raw water circulation pump 4 aeration tank 5, 5' automatic gas valve 6, 6 'automatic water supply valve 7, 7' automatic discharge valve 8 check valve 9 discharge pipe 10 bottom of aeration tank 11 Aeration tank water surface 12 High concentration dissolved gas water

 ────────────────────────────────────────────────── ─── Continued on front page (72) Inventor Takashi Yamanaka 11-1 Haneda Asahimachi, Ota-ku, Tokyo F-term in Ebara Corporation (reference) 4D029 AA01 AB05 CC03 DD01 4G035 AA01 AB05 AE02 AE13

Claims (2)

[Claims] After dissolving high-pressure gas (oxygen or ozone) in raw water in a tank to produce high-concentration dissolved gas water, the tank is connected to an aeration tank to reduce the tank pressure to the aeration tank pressure. An aeration method characterized in that high-concentration dissolved gas water in a tank is discharged into an aeration tank by supplying raw water from the tank to the aeration tank. 2. A plurality of tanks are connected to a high-pressure gas (oxygen or ozone) supply device, a raw water circulation pump, and an aeration tank via an automatic valve, and the tank is controlled by a timer or a command from a dissolved gas concentration detector in the tank. An aeration apparatus characterized in that high-concentration dissolved gas water in a tank is discharged into an aeration tank by alternately switching between supply of high-pressure gas to the tank and supply of raw water.