JP2579295B2 - Wastewater treatment equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a wastewater treatment apparatus for treating sewage, polluted river water, and the like, and more particularly, to a granular carrier to which microorganisms are attached, wastewater, and an oxygen-containing gas. The present invention relates to a fluidized biological treatment type wastewater treatment apparatus which generates a three-phase fluidized bed comprising:

[Conventional technology]

The three-phase fluidized-bed method, in which microorganisms adhere to the surface of the granular carrier fluidized in the biological treatment tank and aeration is performed through an air diffuser arranged in the fluidized bed to remove pollutants in water, Compared to other biofilm methods, the surface area of the carrier used for the attachment of microorganisms can be dramatically increased, so that a large amount of microorganisms can be retained in the tank. As a result, high-speed, high-load processing can be realized. Recently, it has attracted particular attention. However,
An important point was how to prevent the carrier particles from flowing into the treated water due to the ejection of the carrier particles from the fluidized bed which was disturbed by the ventilation.

To prevent this outflow, Japanese Patent Application Laid-Open No. 61-268395 discloses a large number of openings having a size that allows liquids and solid particles to pass through, but does not allow air bubbles to pass into the tank of a fluidized-bed biological treatment apparatus. There is disclosed a technology for preventing carrier particles from flowing into treated water by providing an inclined partition having the same. It is well known in the art that the size of the air bubbles is preferably small in order to effectively dissolve oxygen in water. However, in the above method, since the size of the air bubbles must be increased, the outflow of the carrier can be effectively prevented, but there is a disadvantage that the essential wastewater treatment effect is reduced.

Japanese Patent Application Laid-Open No. 52-137154 discloses that the upper part of a gas-liquid contacting reaction tank is lower than the lower part without preventing the carrier particles from flowing out without the need for an increase in the bubble diameter which causes such a decrease in the wastewater treatment effect. It is formed to have a large cross-sectional area, and a gas-liquid separation wall with a lower cross-sectional area larger than the lower cross-sectional area of the lower part of the tank is arranged in the widened part of the reaction tank to prevent carrier particles from flowing out into the treated water. The disclosed technique is disclosed.

[Problems to be solved by the invention]

The lower right column on page 240, lines 13 to 17 of the above-mentioned publication describes “solid-liquid separation unit 1”.
The granular carriers that have entered into 1 form an interface and become fluidized, and some of the granular carriers settle, return to the space of the dilute phase 10, and there is no bubble up, so no outflow of the granular carriers occurs. " It is described.

However, the gas-solid separation in the method of this technique is only left to the natural separation on the liquid surface in the gas-liquid separation cylinder, so that large bubbles adhering to the carrier particles are naturally generated on the liquid surface. Although they will be separated, a large number of fine small bubbles attached to the carrier particles are unlikely to cause spontaneous separation on the liquid surface. In addition, in this wastewater treatment apparatus, bubbles rising from below in the fluidized bed rich phase 6 in the tank constantly collide, and a completely turbulent state occurs in the fluidized bed rich phase. Not only large bubbles but also countless small bubbles adhere to the carrier particles. Even if the carrier particles with the innumerable small bubbles attached rise, there is no chance that the small bubbles will break off due to the collision with a baffle plate or the like.
The granular carrier that has entered the solid-liquid separation section 11 flows out of the apparatus together with the treated water.

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned conventional problems, and a wastewater treatment apparatus capable of effectively preventing the outflow of carrier particles and performing a stable treatment with a simple and inexpensive configuration. The purpose is to provide.

[Means for solving the problem]

SUMMARY OF THE INVENTION In view of the above, the present invention provides a biological treatment tank for accommodating a particulate carrier for the attachment of microorganisms, a raw water supply pipe for supplying wastewater to be treated to the biological treatment tank, and an oxygen supply pipe at a lower portion of the biological treatment tank. A diffuser tube having a diffuser port for supplying a contained gas, and a fluidized biological treatment type wastewater in which a three-phase fluidized bed composed of a particulate carrier, water and gas is generated in the biological treatment tank to treat the wastewater. In the treatment apparatus, the air diffuser is disposed at a central bottom of the biological treatment tank, and a draft pipe for rectifying the flow of the three-phase fluidized bed is provided above the air diffuser, and further, in water above the draft pipe, A baffle plate having an area larger than the upper opening of the draft tube and having a lower part surrounded by a tray-like green at the bottom is disposed, a treated water outlet is provided above the center of the baffle plate, and a discharge port of the raw water supply pipe is provided. That the outlet is located lower than the baffle And gist wastewater treatment device according to symptoms.

[Action]

In the wastewater treatment apparatus having the above-described configuration, the gas supply from the air diffuser arranged at the lower part of the draft pipe causes an upward flow of the gas-solid mixture by an air lift operation in the draft pipe,
This upward flow collides with a baffle plate above the draft tube, which promotes gas-liquid separation and separates small air bubbles adhering to the granular carrier, after which the granular carrier has a larger area than the upper opening of the draft tube. It is guided outside the draft tube by the plate, and is directed downward at a basin-shaped green part around the baffle plate, resulting in a downward flow between the draft tube and the tank wall. Thereby, a stable circulation flow is generated in the system, and efficient treatment of wastewater is performed. In addition, since the granular carrier flows downward through the outside of the draft tube after colliding with the baffle plate, the water at a higher position than the baffle plate hardly contains the granular carrier, and in particular, the central portion of the baffle plate The above water does not contain particulate carriers,
Therefore, by taking out the treated water from the treated water outlet provided at this position, the outflow of the granular carrier is prevented. Further, by disposing the discharge port of the raw water supply pipe at a position lower than the baffle plate, the wastewater supplied into the tank does not flow directly to the treated water discharge port, and the flow system in the tank is stabilized. Can also.

〔Example〕

 Hereinafter, embodiments of the present invention shown in the drawings will be described.

FIG. 1 is a sectional view of a wastewater treatment apparatus according to one embodiment of the present invention, and FIG. 2 is a top view thereof. In FIG. 1, a three-phase fluidized-bed wastewater treatment apparatus 1 includes a biological treatment tank 2, a raw water supply pipe 3 for supplying wastewater to be treated to the biological treatment tank 2, and an oxygen-containing gas at a lower portion of the biological treatment tank 2. For example, it has an air diffuser 4 having an air diffuser 4A for supplying air.
A granular carrier 5 for adhering microorganisms is accommodated therein. The air diffuser 4A is arranged at the central bottom of the biological treatment tank 2. A draft pipe 6 is provided at the center of the biological treatment tank 2 so as to be above the air diffusion port 4A and to have an upper end immersed in the liquid. A baffle plate 7 having an area larger than the upper opening of is disposed underwater. The periphery of the baffle plate 7 is shaped like a tray-shaped green at the bottom, and the periphery 7A of the baffle plate 7
Is inclined downward outside the draft tube 6. Baffle board 7
Above the baffle plate 7, an outflow pipe 8 is provided, and a treated water outlet 8A at the end thereof is located at the upper center of the baffle plate 7. On the other hand, the discharge port 3A of the raw water supply pipe 3 is disposed outside the draft pipe 6 at a position lower than the baffle plate 7.

Next, the operation of the wastewater treatment apparatus 1 having the above configuration will be described.
By diffusing air from the air diffuser 4 into the wastewater supplied by the raw water supply pipe 3 and stored in the biological treatment tank 2, the particulate carrier 5 is suspended, and a three-phase fluid of solid, gas, and liquid Is formed. This three-phase fluid flows upward in the draft pipe 6 due to the air lift effect of the air from the air diffuser 4A. The granular carrier 5 has activated sludge on its surface,
Purify wastewater by repeating contact with gas. The upwardly flowing three-phase fluid collides with a baffle plate 7 provided above the draft tube 6, whereby a part of the gas is separated, and in particular, fine bubbles adhering to the granular carrier are separated. The flow direction of the granular carrier and the wastewater is regulated, so that a downward flow flows between the draft pipe 6 and the biological treatment tank 2 to return to the lower part of the biological treatment tank 2, and at this time, the raw water is supplied by the raw water supply pipe 3. The incoming inflow water is swirled and is again stirred by the air diffuser 4A. In this way, a circulating flow indicated by an arrow is stably formed in the biological treatment tank 2. The granular carrier 5 having sludge on its surface repeats contact with gas and liquid in this process to purify wastewater. The treated water separated from the granular carrier 5 is guided to the next step from the upper part of the baffle plate 7 by the outflow pipe 8. As a result, the effluent 9 can be stably processed without containing the granular carrier 5.

FIG. 3 is a sectional view of a wastewater treatment apparatus according to another embodiment of the present invention, and FIG. 4 is a top view thereof. 3 and 4, in the upper part of the baffle plate 7 and at the lower end the treated water outlet.
An air lift tube 11 having an air lift tube 11A and an air tube 12 for supplying air for air lift to the air lift tube 11 are provided. The other structure is the same as that of the embodiment shown in FIGS. In the embodiment shown in FIGS. 3 and 4, the treated water can be discharged to a position higher than the liquid level of the biological treatment tank 2 by the air lift pipe 11.

〔The invention's effect〕

As described above, the present invention relates to a three-phase fluidized bed type wastewater treatment apparatus, in which a baffle plate is disposed in water above a draft tube, and the wastewater treatment device passes through the inside and outside of the draft tube in the biological treatment tank. A stable circulation flow can be generated, and wastewater can be treated efficiently.
The granular carrier used for wastewater treatment can be efficiently separated from the treated water, and the treatment efficiency is not reduced. Further, in the apparatus of the present invention, since the granular carrier hardly accompanies the treated water, there is no need for a settling tank for collecting the effluent granular carrier, a facility for returning the collected granular carrier, sludge, etc. in the next step, which is economical. It also has the effect of being a target.

[Brief description of the drawings]

1 is a sectional view of a wastewater treatment apparatus according to one embodiment of the present invention, FIG. 2 is a top view thereof, FIG. 3 is a sectional view of a wastewater treatment apparatus according to another embodiment of the present invention, and FIG. It is a top view. 1 wastewater treatment equipment, 2 biological treatment tank, 3 raw water supply pipe, 3A discharge port, 4 diffuser pipe, 4A diffuser port, 5 granular carrier, 6 draft Tube, 7… Baffle plate, 8… Outflow tube, 8A…
… Treated water outlet, 9… treated water, 11… air lift tube,
11A ... treated water outlet, 12 ... air tube.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) Reference Jikken Sho 60-17271 (JP, Y2)

Claims (1)

(57) [Claims] 1. A biological treatment tank for accommodating a granular carrier for the attachment of microorganisms, a raw water supply pipe for supplying wastewater to be treated to the biological treatment tank, and an oxygen-containing gas supplied to a lower portion of the biological treatment tank. A fluid biological treatment type wastewater treatment apparatus having a diffuser tube having an air diffuser port and generating a three-phase fluidized bed composed of a particulate carrier, water, and gas in the biological treatment tank to perform wastewater treatment; An air diffuser is disposed at the central bottom of the biological treatment tank, and a draft pipe for rectifying the flow of the three-phase fluidized bed is provided above the air diffuser, and an upper opening of the draft pipe is provided in water above the draft pipe. A baffle plate having a larger area and a perimeter shaped like a tray at the bottom is disposed, and a treated water outlet is provided above a central portion of the baffle plate, and a discharge port of the raw water supply pipe is connected to the baffle plate. Wastewater treatment facility characterized by being located at a lower position Apparatus.