CN113830885A

CN113830885A - Defoaming method for aerobic tank of sewage treatment biochemical system

Info

Publication number: CN113830885A
Application number: CN202111251236.9A
Authority: CN
Inventors: 宫建瑞; 郭成; 刘军; 韩珊珊; 乔浩浩; 朱晓桐; 宫磊; 李春泉
Original assignee: Nanjing Wondux Environmental Protection Technology Co ltd
Current assignee: Nanjing Wondux Environmental Protection Technology Co ltd
Priority date: 2021-10-27
Filing date: 2021-10-27
Publication date: 2021-12-24
Anticipated expiration: 2041-10-27
Also published as: CN113830885B

Abstract

The invention relates to the technical field of sewage treatment, in particular to a defoaming method for an aerobic tank of a biochemical system, which comprises the following steps: the jet aeration system provides upward fluid flow and a certain water head height below the liquid level, the defoaming circulating pump flushes high-speed water flow into the guide cylinder through a pipeline, a suction vortex is formed on the water surface, foam is sucked into the guide cylinder and is remixed with activated sludge in the biochemical pool, and the activated sludge decomposes the foam in multiple circulation inside and outside the guide cylinder to realize the defoaming effect. The invention decomposes and eliminates the foam based on the property of the foam, has obvious effect, fully utilizes the common equipment of the biochemical system, does not need to add a defoaming agent, and reduces the investment and operation cost of the system.

Description

Defoaming method for aerobic tank of sewage treatment biochemical system

Technical Field

The invention relates to the technical field of sewage treatment, in particular to a defoaming method for an aerobic tank of a sewage treatment biochemical system.

Background

The biochemical treatment method is the most widely applied treatment method of a sewage treatment plant. For most sewage treatment plants adopting biochemical treatment in the world, the problem of surface foam is ubiquitous, which causes difficulty in operation, operation and control of the sewage treatment plants and also seriously affects the quality of effluent water.

At present, two main defoaming methods are available, namely defoaming by using a defoaming agent and physical defoaming. The method for adding the defoaming agent is the most widely applied defoaming method in various industries at present, and the method has the advantages of greatly improving defoaming efficiency, being convenient to use and the like, but the key is to find a proper and efficient defoaming agent. Meanwhile, the use of the defoaming agent is performed throughout the operation of the system, and the operation cost is increased.

The physical defoaming method mainly comprises mechanical defoaming, filter screen placement or baffle addition, freezing, heating, steam, high-speed centrifugation, pressurization and decompression, high-frequency vibration, instantaneous discharge and the like. However, in the process of physical defoaming, environmental factors have strong restrictions on the use of these methods, and if a proper defoaming method is not selected, the defoaming rate is seriously affected.

Disclosure of Invention

In order to overcome the defects of the prior art, improve the defoaming efficiency and reduce the system operation cost, the invention aims to provide the defoaming method for the aerobic tank of the sewage treatment biochemical system, which does not need to add a defoaming agent or other medicaments into the system and fully utilizes the biochemical system equipment.

The purpose of the invention is realized by adopting the following technical scheme:

a defoaming method for an aerobic pool of a sewage treatment biochemical system comprises the following steps: the jet aeration system provides upward fluid flow and a certain water head height below the liquid level, the defoaming circulating pump flushes high-speed water flow into the guide cylinder through a pipeline, the water surface height difference and the pressure difference formed by the two modes lead the water surface to form suction vortex, the foam is sucked into the guide cylinder and is remixed with activated sludge in the biochemical pool, and the activated sludge decomposes the foam in multiple cycles inside and outside the guide cylinder to realize the defoaming effect.

Further, the defoaming method comprises the following steps: reduce the exit area at defoaming circulating pump pipeline export to provide faster play water velocity of flow, form higher pressure differential, satisfy the surface of water suction vortex formation condition.

Furthermore, the defoaming method raises the position of the jet aerator to 4-5 m below the liquid level so as to provide sufficient rising flow velocity and water head height outside the guide cylinder.

Furthermore, the defoaming method inserts an air pipe into the defoaming circulating pipe, and carries out jet oxygenation on sewage by bringing air into the high-speed flowing water flow, so that the aeration rate of the system is reduced, and the generation amount of foam is reduced.

Furthermore, the defoaming method guide cylinder is fixed on the side wall of the aerobic tank, the length of the guide cylinder is 4 meters, and the installation position of the guide cylinder is 0.5 meter below the liquid level.

Furthermore, the defoaming method needs to be used after the biochemical system is stably debugged and the activated sludge has normal capability of decomposing organic matters.

Furthermore, the method for reducing the outlet area of the defoaming circulating pipe is designed in an inverted circular table mode.

Furthermore, the flow speed of the water outlet of the gate of the defoaming circulating pipe needs to reach 10-15 m/s.

Furthermore, the air pipe and the defoaming circulating water pipe should keep a certain concentricity, and a control valve is arranged at the upper part of the air pipe to adjust the air input.

Has the advantages that:

the invention has the advantages that defoaming agent or other chemical agents are not needed, the operation cost of biochemical treatment is greatly reduced, biochemical treatment system equipment such as a circulating pump and a jet aerator is fully utilized, only a guide cylinder and an air pipe are added, the price is low, a defoaming system is not needed to be additionally added, the operation effect is stable, and the operation is convenient.

Drawings

FIG. 1 is a schematic diagram of a defoaming structure used in the defoaming method of the aerobic tank of the sewage treatment biochemical system. 1. A circulating pump 2, an air pipe 3, a guide cylinder 4 and a jet aerator.

Detailed Description

The invention provides upward fluid flow and a certain water head height below the liquid level through the jet aeration system, the defoaming circulating pump flushes high-speed water flow into the guide cylinder through a pipeline, the height difference and the pressure difference of the water surface formed by the two modes cause the water surface to form suction vortex, foam is sucked into the guide cylinder and is mixed with activated sludge in the biochemical pool again, and the foam is decomposed by the activated sludge in multiple cycles inside and outside the guide cylinder, so that the defoaming effect is realized.

Specifically, the defoaming method for the aerobic tank of the sewage treatment biochemical system specifically comprises the following steps: the defoaming circulating pump pumps circulating sewage into the guide shell through the defoaming circulating pipe, when the sewage enters the guide shell, the inner surface of the shell forms a suction vortex due to high flow velocity, the foam on the surface of the sewage enters the aerobic tank at the bottom of the guide shell along with the vortex to be mixed with activated sludge, and then rises to the liquid level under the action of airflow of the jet aerator, and the foam is decomposed after repeated reciprocating circulation.

Reduce the exit area at defoaming circulating pump pipeline export to provide faster play water velocity of flow, form higher pressure differential, satisfy the surface of water suction vortex formation condition.

The method for reducing the outlet area of the defoaming circulating pipe is designed in an inverted circular truncated cone shape, and the height of the inverted circular truncated cone is 0.25-0.4 m. The flow velocity of the outlet water of the defoaming circulating pipe gate is required to reach 10-15 m/s.

The defoaming method lifts the position of the jet aerator to 4-5 meters below the liquid level so as to provide sufficient rising flow velocity and water head height outside the guide cylinder.

According to the defoaming method, the air pipe is inserted into the defoaming circulating pipe, and the sewage is subjected to jet oxygenation by bringing air into the high-speed flowing water flow, so that the aeration rate of the system is reduced, and the foam generation amount is reduced.

Specifically, the air pipe and the defoaming circulating water pipe should keep a certain concentricity, and a control valve is arranged at the upper part of the air pipe to adjust the air input.

The defoaming method is characterized in that the guide cylinder is fixed on the side wall of the aerobic tank, the length of the guide cylinder is 4 meters, and the installation position of the guide cylinder is 0.5 meter below the liquid level.

The defoaming method needs to be used after the biochemical system is stably debugged and the activated sludge has normal capability of decomposing organic matters.

Claims

1. A defoaming method for an aerobic pool of a sewage treatment biochemical system is characterized by comprising the following steps: the jet aeration system provides upward fluid flow and a certain water head height below the liquid level, the defoaming circulating pump flushes high-speed water flow into the guide cylinder through a pipeline, the water surface height difference and the pressure difference formed by the two modes lead the water surface to form suction vortex, the foam is sucked into the guide cylinder and is remixed with activated sludge in the biochemical pool, and the activated sludge decomposes the foam in multiple cycles inside and outside the guide cylinder to realize the defoaming effect.

2. The aerobic pool defoaming method of claim 1, wherein the defoaming method comprises the following steps: reduce the exit area at defoaming circulating pump pipeline export to provide faster play water velocity of flow, form higher pressure differential, satisfy the surface of water suction vortex formation condition.

3. The aerobic pool defoaming method of claim 1, wherein the position of the jet aerator is raised to 4-5 m below the liquid level so as to provide sufficient rising flow velocity and water head height outside the guide cylinder.

4. The aerobic pool defoaming method of claim 1, wherein an air pipe is inserted into the defoaming circulation pipe, and air is introduced by the high-speed flowing water flow to carry out jet oxygenation on the sewage, so that the aeration rate of the system is reduced, and the generation amount of foam is reduced.

5. The aerobic pool defoaming method of claim 1, wherein the defoaming method draft tube is fixed on the side wall of the aerobic pool, has a length of 4m, and is installed at a position 0.5 m below the liquid level.

6. The aerobic pool defoaming method of claim 1, wherein the defoaming method is performed after the biochemical system is adjusted and stabilized and the activated sludge has normal capability of decomposing organic matters.

7. The aerobic tank defoaming method of claim 2, wherein the outlet area reducing method of the defoaming circulation pipe is designed in an inverted circular table type.

8. The aerobic pool defoaming method of claim 2, wherein the flow velocity of the outlet water from the nozzle of the defoaming circulation pipe is 10m/s to 15 m/s.

9. The aerobic pool defoaming method of claim 4, wherein the air pipe and the defoaming circulating water pipe should be kept in a certain concentricity, and the upper part of the air pipe is provided with a control valve for adjusting the air input.