JP2002205087A - Air diffuser - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air diffusing equipment, in which oxygen dissolving efficiency is improved by eliminating the effect of sludge and retaining fine bubbles in a vessel for a long time. SOLUTION: A dissolving part 3 and reaction part 4 communicating with the dissolving part 3 through a separation means 2 are provided in the vessel, a diffusing pipe 8 is arranged in the dissolving part 3, a circulation lines 10 communicating with the dissolving part 3 at the base end side and communicating with the reaction part 4 at the tip part is provided and the tip side of the circulation line is opened toward a direction along the vessel bottom surface of the reaction part or toward a direction having a prescribed angle to the vessel bottom surface of the reaction part 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an air diffuser,
The present invention relates to a technique for supplying oxygen to activated sludge in a water treatment facility.

[0002]

2. Description of the Related Art Conventionally, in a membrane separation activated sludge method, which is one of the activated sludge methods, an air diffuser is disposed below a membrane separator immersed in an aeration tank, and air diffused from the air diffuser is provided. The mixed liquid in the tank including the activated sludge in the aeration tank is aerated, and the membrane surface of the membrane separation device is washed by the upward flow of the solid-gas-liquid mixed phase generated by the rise of the diffused air.

[0003] Oxygen required for biological treatment in the membrane separation activated sludge method is secured by supplying a predetermined amount of aerated air based on the efficiency of dissolving oxygen in activated sludge with a predetermined aerated blower. Increasing the oxygen dissolving efficiency is desirable because it reduces power consumption by downsizing the aeration blower and shortening the aeration time.

[0004] For this purpose, the diameter of the air outlet of the diffuser tube is reduced to generate fine air bubbles, or air bubbles diffused from the diffuser tube by a strong water flow provided with a mechanical stirring device. It is finely distributed.

[0005]

However, in order to reduce air bubbles by a mechanical stirrer, power for driving the mechanical stirrer is required, and a practical bubble size is limited in terms of power efficiency. is there. Also, when the diameter of the air outlet of the air diffuser is reduced, the air outlet is likely to be blocked by impurities in water flowing backward into the air diffuser when the air diffusion is stopped, and the opening degree in the air diffuser is reduced. Air is intensively ejected from some of the air ejection ports, and the air bubbles at that location increase. Furthermore, in the activated sludge, the dissolution phenomenon occurs through the interface between water and gas. When the sludge intervenes therein, the sludge inhibits the contact between water and gas, and the oxygen dissolving efficiency is greatly reduced depending on the properties of the sludge.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and provides an aeration apparatus capable of eliminating adverse effects of sludge, retaining fine air bubbles in a tank for a long time, and improving oxygen dissolving efficiency. The purpose is to:

[0007]

In order to solve the above-mentioned problems, an aeration apparatus of the present invention according to claim 1 includes a dissolving section and a reaction section communicating with the dissolving section via a separating means in a tank. Provided,
A diffuser tube is arranged in the dissolving part, and a circulation system is provided in which the base end communicates with the dissolving part and the distal end communicates with the reaction part, and the distal end of the circulation system is directed toward the direction along the tank bottom of the reaction part or the reaction part. It opens in a direction having a predetermined angle with respect to the bottom of the tank.

In the above construction, the separating means comprises a screen, a nonwoven fabric, a membrane, etc., and the mixed liquid in the tank of the reaction section is supplied to the dissolving section through the separation means, so that the activated sludge in the reaction section and foreign substances in the sludge are supplied. Is prevented from flowing into the dissolving section, the sludge properties of the mixed solution in the tank in the dissolving section are modified to those containing no foreign matter, and the sludge concentration is maintained at a low level.

The liquid mixture in the tank in the dissolving section has a low sludge concentration and does not have any foreign matter that may block the air outlet of the diffuser tube. Spraying can be continued for a long period of time, and the oxygen dissolving efficiency can be increased by making the air to be diffused into minute bubbles, and sludge that inhibits the dissolving phenomenon through the interface between water and gas is generated. Since it is small, the oxygen dissolving efficiency increases.

[0010] The mixed solution in the tank is circulated from the dissolving section to the reaction section through a circulating system, and is treated by a biological reaction under sufficient dissolved oxygen. At this time, the mixed solution in the tank that jets out to the reaction section from the opening on the tip side of the circulation system jets along the tank bottom of the reaction section or at a predetermined angle with respect to the tank bottom of the reaction section, thereby entering the reaction section. A circulating flow is generated and the liquid mixture in the tank is stirred.

According to a second aspect of the present invention, there is provided a diffuser according to the present invention, wherein a dissolving section and a reaction section communicating with the dissolving section via separation means are provided in a tank, and an air diffusing tube is disposed in the dissolving section. A circulating system is provided that communicates with the dissolving section and the leading end communicates with the reaction section, and the leading end of the circulating system opens in a direction along the membrane surface of the separation means.

According to the above-described structure, the mixed solution in the tank in the dissolving section which jets out from the opening on the tip side of the circulation system to the reaction section flows as a sweep along the membrane surface of the separation means, and flows along the membrane surface of the separation means. Wash. Moreover, the mixed liquid in the tank in the dissolving section has a low sludge concentration,
Since no foreign matter is contained, a high cleaning effect can be obtained.

According to a third aspect of the present invention, there is provided a diffuser according to the present invention, wherein a dissolving unit and a reaction unit communicating with the dissolving unit via separation means are provided in the tank, and an air diffuser is disposed in the dissolving unit. A circulation system is provided in communication with the dissolving section, the leading end side communicating with the reaction section, and an air diffuser is disposed in the reaction section.

According to the above-described structure, the upward flow of the solid-gas-liquid mixed phase generated by the air-lifting action of the air ejected from the air diffuser of the reaction section flows as a sweep along the membrane surface of the separation means. Wash the membrane surface.

According to a fourth aspect of the present invention, there is provided a diffuser according to the present invention, wherein a dissolving unit and a reaction unit communicating with the dissolving unit via separation means are provided in the tank, and a diffusing tube is disposed in the dissolving unit. An immersion type membrane separation device is provided, a circulation system is provided in which the base end communicates with the dissolving section and the tip end communicates with the reaction section, and the tip side of the circulation system opens at a position below the immersion type membrane separation device.

According to the above-described configuration, the mixed solution in the tank in the dissolving section that jets out from the opening on the distal end side of the circulation system to the reaction section flows as a sweep along the membrane surface of the immersion type membrane separation device, and flows in the dissolving section. Since the liquid mixture in the tank has a low sludge concentration and does not contain foreign matter,
A high cleaning effect is obtained for the membrane surface of the immersion type membrane separation device.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a dissolving section 3 and a reaction section 4 which are communicated with each other by a separating means 2 composed of a screen, a nonwoven fabric, a separation membrane and the like are formed inside a tank body 1.

An inflow pipe 5 for supplying water to be treated is opened in the dissolving section 3 (possibly also in the reaction section 4), and an outflow pipe 6 for taking out treated water is opened in the reaction section 4. Has an air diffuser 8 connected to a blower 7. A circulation system 10 having a circulation pump 9 is provided between the melting section 3 and the reaction section 4. The circulation system 10 has a base end communicating with the bottom of the dissolving section 3 and a distal end communicating with the reaction section 4 oriented in a direction along the tank bottom or in a direction having a predetermined angle with respect to the tank bottom of the reaction section 4. Open.

On one side of the reaction section 4 is a submerged membrane separation device 11.
Is provided. The immersion type membrane separation device 11 has a plurality of flat plate type membrane cartridges 12 each having an organic membrane arranged on a filter plate arranged vertically and parallel to each other, and connected to a blower 13 below the flat plate type cartridge 12. The suction pump 16 is provided in the treatment water pipe 15 which communicates with the permeated liquid flow path of each flat membrane cartridge 12.

With the above configuration, the liquid mixture in the tank of the dissolving section 3 is circulated to the reaction section 4 through the circulation system 10 by the circulation pump 9, thereby maintaining the water level of the dissolving section 3 lower than the water level of the reaction section 4. Create a head difference between the two.

In this state, the liquid mixture in the tank of the reaction section 4 flows into the dissolving section 3 through the separation means 2 using the head difference as a driving pressure. At this time, the separation means 2 suppresses the activated sludge in the liquid mixture in the tank of the reaction section 4 and the foreign matter in the sludge from flowing into the dissolving section 3. And the sludge concentration is reduced.

In the dissolving section 3, air supplied from a blower 7 is blown out from an air diffuser 8 to aerate the mixed solution in the tank. At this time, since the mixed solution in the tank of the dissolving section 3 has a low sludge concentration and does not contain foreign matter, the air outlet of the diffuser 8 does not block, and the diameter of the air outlet can be reduced. This makes it possible to continue the state in which air is diffused as minute bubbles for a long time, and the minute bubbles increase the oxygen dissolving efficiency. Further, the amount of sludge that hinders the dissolution phenomenon through the interface between water and gas is small, so that the oxygen dissolving efficiency increases.

In the dissolving section 3, the circulating system 10 opened at the bottom of the tank sucks the mixed liquid in the tank, so that the mixed liquid in the tank flows downward from the upper region to the lower region. On the other hand, since the air diffused from the air diffuser 8 rises from the lower region toward the upper region, the mixed liquid in the tank and the aerated air come into gas-liquid countercurrent contact. For this reason, the rise of the air bubbles is suppressed by the downward flow of the mixed liquid in the tank, and the residence time of the bubbles in the tank increases,
Oxygen dissolution efficiency increases. The mixed solution in the tank in which oxygen is sufficiently dissolved in the dissolving section 3 is circulated from the dissolving section 3 to the reaction section 4 through the circulation system 10, and is treated by a biological reaction under sufficient dissolved oxygen.

At this time, the mixed liquid in the tank which is ejected from the opening on the tip side of the circulation system 10 to the reaction section 4 is ejected along the tank bottom of the reaction section 4 or at a predetermined angle with respect to the tank bottom of the reaction section 4. As a result, a circulating flow is generated inside the reaction section 4 and the mixture in the tank is stirred, the reaction efficiency between the activated sludge, oxygen and pollutants is increased, the biological reaction is promoted, and the power of the circulation pump 9 is wasted. And contribute to the improvement of the reaction efficiency.

The immersion type membrane separation apparatus 11 filters the mixed solution in the tank of the reaction section 4 with the flat type membrane cartridge 12 using the suction pressure of the suction pump 16 as the driving pressure, and filters the membrane permeate into the treated water pipe 1.
Remove through 5. The air supplied from the blower 13 is blown out from the air diffuser 14, and the mixed liquid in the tank is supplied to the membrane surface of the flat membrane cartridge 12 in a cross flow by the upward flow of the solid-gas-liquid multiphase flow generated by the air lift action of the air. In addition, the upward flow acts as a scavenging flow to clean the membrane surface.

FIG. 2 shows another embodiment of the present invention. In FIG. 2, the tip of the circulating system 10 is
The opening is opened in the direction along the membrane surface of the separation means 2, that is, upward.

With the above configuration, the mixed solution in the tank of the dissolving section 3 squirting into the reaction section 4 from the opening on the tip side of the circulation system 10 flows as a sweep along the membrane surface of the separating means 2, 2 is washed. Moreover, the mixed solution in the tank of the dissolving section 3 has a low sludge concentration and does not contain any foreign matter, so that a high cleaning effect can be obtained.

FIG. 3 shows another embodiment of the present invention. In FIG. 3, an air diffuser 18 connected to a blower 17 is disposed in the reaction section 4 near the membrane surface of the separation means 2, and the tip side of the circulating system 10 is below the air diffuser 14 of the immersion type membrane separator 11. Open at the location.

With the above configuration, the diffuser 1 of the reaction section 4
The upward flow of the solid-gas-liquid mixed phase generated by the air-lifting action of the air ejected from 8 flows as a sweep along the membrane surface of the separation means 2 to clean the membrane surface of the separation means 2.

On the other hand, the mixed solution in the tank of the dissolving unit 3 squirting into the reaction unit 4 from the opening on the tip side of the circulation system 10 flows as a sweep along the membrane surface of the immersion type membrane separation device 11, Since the mixed liquid in the tank of 3 has low sludge concentration and does not contain foreign matter,
A high cleaning effect is obtained for the membrane surface of the immersion type membrane separation device 11.

[0031]

As described above, according to the present invention, activated sludge in the mixed solution in the tank of the reaction section and foreign matter in the sludge are suppressed from flowing into the melting section by the separation means, and the mixing in the tank of the melting section is suppressed. By modifying the sludge properties of the liquid to lower the sludge concentration, foreign matter does not cause the air outlet of the air diffuser to erupt, and the diameter of the air outlet of the air diffuser is reduced to diffuse fine air bubbles. The worrying state can be continued for a long time, and the oxygen dissolving efficiency can be increased by the minute bubbles. Furthermore, the oxygen dissolving efficiency can be improved by eliminating sludge that inhibits the dissolving phenomenon through the interface between water and gas.
In the dissolving section, the mixed solution in the tank is flowed in a downward flow, so that the air diffused from the air diffuser is brought into gas-liquid countercurrent contact, the rise of air bubbles is suppressed by the downward flow, and the residence time of the bubbles in the tank is reduced. By increasing the length, the oxygen dissolution efficiency can be increased.

The liquid mixture in the tank spouting from the opening on the tip side of the circulation system to the reaction section is jetted along the bottom of the reaction section or at a predetermined angle to the bottom of the reaction section, and By stirring the mixture, the reaction efficiency between the activated sludge, oxygen and pollutants is increased to promote the biological reaction, and the power of the circulation system can be contributed to the improvement of the reaction efficiency without waste.

The mixed liquid in the tank of the dissolving section which jets out from the opening on the tip side of the circulation system to the reaction section flows as a sweep along the membrane surface of the separation means, and the mixed liquid in the tank of the dissolving section has a sludge concentration. By not including low foreign matter, a high cleaning effect can be obtained.

The upward flow of the solid-gas-liquid mixed phase generated by the air-lifting action of the air ejected from the air diffuser of the reaction section flows as a sweep along the membrane surface of the separation means to clean the membrane surface of the separation means. be able to.

The liquid mixture in the dissolving section, which jets into the reaction section from the opening on the tip side of the circulation system, flows as a sweep along the membrane surface of the immersion type membrane separation device, and the mixed liquid in the dissolving section tank flows. Since the sludge concentration is low and contains no foreign matter, a high cleaning effect can be obtained on the membrane surface of the immersion type membrane separation device.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an air diffuser according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing an air diffuser according to another embodiment of the present invention.

FIG. 3 is a schematic view showing an air diffuser according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tank body 2 Separation means 3 Melting part 4 Reaction part 5 Inflow pipe 6 Outflow pipe 7 Blower 8 Diffusion pipe 9 Circulation pump 10 Circulation system 11 Immersion type membrane separation device 12 Flat membrane cartridge 13 Blower 14 Diffusion pipe 15 Treatment water pipe 16 Suction pump

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tatsuya Uejima 2-47, Shikitsu Higashi 1-chome, Naniwa-ku, Osaka-shi, Osaka (72) Inventor Masaharu Nishi Higashi-ichi Shikitsu, Naniwa-ku, Osaka, Osaka No. 2-47 F-term in Kubota Corporation (reference) 4D006 GA02 HA41 KA01 KA51 KB22 KC02 KC14 MA03 PB08 PC62 4D028 BC13 BC17 BC24 4D029 AA01 AA09 AB05 DD01

Claims (4)

[Claims] 1. A dissolving section and a reaction section communicating with the dissolving section via a separating means are provided in a tank, and an air diffuser is disposed in the dissolving section.
A circulation system is provided in which the base end communicates with the dissolving part and the distal end communicates with the reaction part, and the front end of the circulation system is directed in a direction along the tank bottom of the reaction part, or at a predetermined angle with respect to the tank bottom of the reaction part. A diffuser, characterized by opening in the direction of the air. 2. A dissolving section and a reaction section communicating with the dissolving section via a separation means are provided in the tank, and an air diffuser is disposed in the dissolving section.
An air diffuser, wherein a circulation system is provided in which a base end communicates with a dissolving part and a distal end communicates with a reaction part, and a distal end of the circulation system is opened in a direction along a membrane surface of the separation means. 3. A dissolving part and a reaction part communicating with the dissolving part via a separating means are provided in the tank, and an air diffuser is disposed in the dissolving part.
A diffuser, wherein a circulation system is provided in which a base end communicates with a dissolving part and a distal end communicates with a reaction part, and an air diffuser is disposed in the reaction part. 4. A dissolving part and a reaction part communicating with the dissolving part via a separating means are provided in the tank, and an air diffuser is disposed in the dissolving part.
A immersion type membrane separation device is arranged in the reaction section, a circulation system is provided in which the base side communicates with the dissolving section and the tip side communicates with the reaction section, and the tip side of the circulation system is opened at a position below the immersion type membrane separation apparatus. Aeration equipment characterized by the following.