JPH09117606A - Defoaming device for waste water treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To destroy foam at low cost by a method wherein an annular receiving trough with water scattering port is formed on the inner edge of the lower end of a cylindrical defoaming shell passing through the upper section of a closed waste water treatment tank and a water scattering disk with lower surface blade is disposed on the trough to form a scattering water falling space between the disk and the inner wall of the shell. SOLUTION: A rotation axis 15 passes through the center of a foam scattering prevention chamber 12 and a middle portion of the axis is supported by a foam prevention plate with air holes 16a or a radial supporting frame 16 and an end of the axis reaches the interior of a defoaming shell 11. And a water scattering disk 20 having defoaming blades 21 on the lower surface thereof is mounted to the end of the axis. The diameter of the disk is such that the outer periphery of the disk comes just above a trough inner wall 26 to form an annular gap P between the periphery of the disk and the inner wall of the shell 11. Foam produced in the chamber rises from an opening 24 and is crushed by the rotating blades 21 and crushed small pieces of foam rise through the gap P and are moved on the disk 20 by centrifugal force, and since water is falling from the periphery of the disk through the gap P, the pieces of foam are captured by water and fall down into a receiving trough 25 and fall down in the chamber from a scatting port 27 in the foam of droplets.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a closed wastewater treatment device or a device for mechanically destroying bubbles generated in an aeration tank.

[0002]

2. Description of the Related Art Conventionally, as a means for defoaming bubbles in a closed type wastewater treatment apparatus, a method of adding a defoaming agent such as a silicone type or wax emulsion, or spray water alone or in combination has been carried out. The former requires a storage tank in addition to the cost of the defoamer, and the latter requires a large amount of water, so a large pump must be installed.

[0003]

DISCLOSURE OF THE INVENTION The present invention provides a defoaming device which does not use an antifoaming agent and which can reduce the installation space of defoaming-related devices such as a storage tank or a pump at low cost.

[0004]

According to the apparatus of the present invention, an annular gutter with a water spout is formed on the inner edge of the lower end of a cylindrical defoaming cylinder mounted so as to penetrate through the upper part of a closed type wastewater treatment tank, and at the same time, inside the cylinder. A sprinkler disc with a lower surface blade axially attached to a vertical drive shaft is provided at the upper part of the gutter and is provided with a sprinkling drop gap formed between the sprinkler disc and the inner wall of the trunk. Is configured to be supplied. The sprinkling drop gap between the sprinkling disc and the shell wall is such that the sprinkling from the disc periphery effectively flows down into the annular gutter, and the outer edge of the disc is located above the gutter inner wall. Good to do. The spout of the annular trough may be provided on the side surface in addition to the bottom surface of the trough.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an overall view of the apparatus applied to a three-phase flow tank, in which 1 is a three-phase flow tank, and the waste liquid to be treated to be supplied is aerated by aeration with a microorganism-immobilized carrier. It circulates inside. 3 is an aerator, 4 is a buffer plate,
5 is a current plate, 6 is an overflow weir, and 7 is a hood that seals the upper part of the tank. Reference numeral 10 is a device of the present invention, and as shown in FIG. 2, a cylindrical defoaming cylinder 11 is fixedly installed through the hood 7. 12 is a bubble scattering prevention tube provided with a vent 12a,
Reference numeral 13 is a motor stand, and 14 is a variable speed motor. 1
Reference numeral 5 denotes a rotary shaft, which penetrates the center of the bubble scattering prevention chamber 12 and has an intermediate portion at a foam stop plate with a vent hole 16a or a radial support frame 1
It is supported 17 by 6, and the shaft end reaches the inside of the defoaming cylinder 11. A sprinkling disc 20 having a defoaming blade 21 on the lower surface is axially attached to the shaft end. The disk diameter is such that the outer circumference of the disk is a trough inner wall 2 which will be described later so as to form an annular gap P with the trunk wall.
It is better to be located just above 6. The blade 21 is an L-shaped or flat-shaped plate on the lower surface of the circular plate 20 having 5 to 6 axial symmetry or FIG.
It is fixed eccentrically and radially. 23 is the body 1
An annular gutter 25 is formed at an inner edge of the lower end opening 24 of the tank insertion side of No. 1 by an inner wall 26 integrally connected to the trunk, and a spout 27 is bored at a bottom part of the gutter. There is. A sprinkling supply pipe 30 sprinkles water from a spout 31 which is connected to a pump (not shown) and which is opened on the sprinkling disc 20. In the above device, the rotational speed of the sprinkling disk is within a range in which the circumferential speed of the blade tip is 3 to 6 m / s, and when the speed is 6 m / s or more, the bubbles jump frequently and the bubbles reach above the disk. It is not preferable because it will scatter. The amount of water sprayed is 10 to 50 L / Hr. Furthermore, when the superficial velocity of the air in the body is 0.7 m / s or more, bubbles are lifted up to the upper part of the body.
It is preferable to set the throat portion diameter D so as to be in the range of m / s to 0.7 m / s. In the above apparatus, the bubbles generated in the tank rise through the opening 24 but are crushed by the rotating blade 21, and the crushed small pieces try to rise through the gap P, but move on the sprinkling disk 20 by centrifugal force. The flowing water flowing down from the peripheral edge through the gap is trapped by the flowing water and flows down into the trough 25 to form droplets from the sprinkling port 27 and drop into the tank. The droplets also contribute to breaking bubbles on the water surface.

[0006]

Example A closed type three-phase fluidized total wastewater treatment device with an effective volume of 56 m ³ and an aeration rate of 11 Nm ³ / min was used, and the superficial velocity was 0.5 m / min.
The waste water of the water-soluble ink manufacturing plant was treated by installing the apparatus shown in FIGS. 2 and 3 in which the throat diameter portion D was set to 0.7 m so that the time became sec. Circumferential velocity of the rotating blade 5.23m / s
By operating (motor rotation speed 166 rpm) and water sprinkling amount of 20 L / Hr, the bubbles generated in the tank could be defoamed without using the defoaming agent. The amount of water used for defoaming the waste water by the spray method is 14,000 L / H.
r, the present invention saves a large amount of water and water supply equipment.

[0007]

[Effect] The present invention can save a large amount of water, which is conventionally required, or does not use an antifoaming agent at all, so that the treatment cost can be greatly reduced and it is economical, and no special water supply facility or storage tank is required. Therefore, there is an effect that the equipment area can be saved.

[Brief description of the drawings]

FIG. 1 is an overall view of the apparatus of the present invention installed on a three-phase flow tank.

FIG. 2 is a sectional view of an essential part of the device of the present invention.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

[Explanation of symbols]

 11 Defoaming cylinder 12 Foam scattering prevention chamber 16 Foam stop plate 20 Sprinkling disk 21 Defoaming rotary blade 23 Throat throat 24 Opening 25 Annular gutter 26 Inner wall 27 Sprinkling port 30 Sprinkling supply pipe 31 Discharging port

Claims (2)

[Claims] 1. A lower surface of a cylindrical defoaming cylinder mounted penetrating an upper part of a closed type waste water treatment tank, wherein an annular gutter with a water spout is formed on an inner edge of a lower end of the cylindrical defoaming cylinder, and a vertical drive shaft is axially attached to the cylinder. A waste water characterized in that a water sprinkling disc with a blade is located above the trough and is provided with a sprinkling drop gap between it and the inner wall of the trunk, and defoaming water sprinkling is supplied onto the water sprinkling disc. Defoaming device for processing equipment. 2. The defoaming device according to claim 1, wherein a bubble scattering prevention chamber is provided above the water sprinkling disk via a foam stopping plate which also serves as a bearing support for the drive shaft.