KR200264175Y1 - Sludge Thickning Equipment. - Google Patents

Abstract

This paper relates to a concentrating device for the first settling sludge and surplus activated sludge from a sewage treatment plant or wastewater treatment plant. The surplus activated sludge from the final settler is transferred to the sedimentation site at the entrance of the sewage treatment plant. In this case, the excess activated sludge and influent sewage are contacted and mixed for about 1 hour, denitrification occurs while maintaining anaerobic condition, and then the sludge is transferred to the initial settler using an inflow pump. It is possible to produce concentrated sludge with stable concentration by improving concentration effect.

In this way, it is possible to increase the degree of concentration in the concentration tank and transfer the highly concentrated sludge to the digester to increase the digestion efficiency, thereby increasing the amount of methane gas generated in the digester and reducing the amount of digested sludge, which is economically effective and reduces the amount of sludge produced. There is a protective effect, and the return load is reduced by increasing the concentration and digestion rate, thereby reducing the water treatment load, thereby helping to stabilize the water treatment.

Description

Sludge Concentrator {Sludge Thickning Equipment. }

The present invention relates to a technique for concentrating the activated sludge from the initial settler sludge and the surplus sludge from the final settler in a sewage treatment plant or wastewater treatment plant.

Conventionally, in order to concentrate the above sludge in a gravity type concentration tank, the sludge and surplus activated sludge of the initial settler were mixed in a distribution tank at the front of the concentration tank and concentrated in the concentration tank.

In addition, when the state of the surplus activated sludge was bad or the amount of surplus activated sludge was large, the surplus activated sludge was returned to the initial settler to be precipitated.

In the conventional method as described above, there is the following problem, the concentration in the gravity concentration tank was not well.

The amount of surplus activated sludge is determined based on the state in which it is operating ideally at the time of design, and the size and load of the thickener is determined accordingly. Is varied in various ways and varies from time to time.For example, bulking or other reasons may cause problems with the settling of activated sludge.In this case, the concentration of surplus activated sludge is much lower than the designed value and accordingly The amount of surplus activated sludge is much higher than the designed value (severely up to several times the designed value), and excessive concentration of sludge flows into the thickening tank, and the gravity type thickening tank is hydraulically insufficient in dwelling time. Concentrated to low concentration of sludge The concentration of the sludge is extremely lower than the design value (typically 4% DS).

In this case, if the surplus activated sludge is transferred to the first settler, mixed with sewage, settled, and concentrated in a gravity tank, the above problems can be alleviated.In this case, the settling is prevented due to the generation of gas by denitrification in the first settler. A large amount of scum is generated on the surface of the sedimentation basin, the concentration of sludge decreases, and the quality of the initial sediment effluent is deteriorated.

The reason for this is that if the standard activated sludge method properly manages the SRT (sludge residence time, which is usually 3 to 4 days), the nitrification does not occur in the abandonment tank, but it is difficult to properly manage the SRT in the field for various reasons. In recent years, the F / M ratio is lowered and the SRT is operated longer than the standard to lower the BOD of the effluent, so that some nitrification is unavoidable in the aeration tank and complete nitrification occurs in the advanced treatment plant for biological denitrification. When activated sludge comes into contact with the sewage of an organic carbon source richest settling cell, denitrification occurs under anaerobic conditions and depends on the water temperature. However, the test showed that the sludge was injured by gas generation within about 1 hour during the high water temperature.

The holding time of the initial settler is usually 2 hours, so it is obvious that the sludge rises within 1 hour, which would interfere with the settling.

In addition, even under normal operating conditions, if excess activated sludge and the first settling sludge are mixed in the thickener, sludge may be injured by gas generation within one hour during the high temperature season as shown in the above example, preventing the settling and concentration in the thickener. Appeared to be.

Due to the various reasons described above, the conventional gravity type thickening tank was not concentrated well and this caused various problems. The main problem is that the sludge with low concentration is transferred to the digester and the digestion is incomplete due to lack of hydraulic residence time and lack of solids. Sludge reduction in the digester was not properly achieved, and the amount of sludge produced increased. Finally, the amount of dewatered sludge cake increased, resulting in increased sludge disposal costs, difficulty in disposing of sludge (reclamation, etc.), and the lack of methane gas generation. As it is necessary to supply a large amount of fuel from the outside such as light oil to keep the temperature at a proper temperature, it is very economically burdensome and the return load in the concentration tank and the digestion tank increases, which leads to an increase in the load of the water treatment system, which also causes many difficulties in water treatment. It became.

The technical problem to be achieved by the present invention is to provide a concentrating device so that the sludge is concentrated in the thickener tank effectively by reducing the amount of sludge supplied to the thickener tank so as not to cause a gas generation in the gravity tank.

1 is a block diagram showing a configuration state of the present invention

2 is a block diagram showing another embodiment of the present invention

Explanation of symbols for important parts of the drawings

1. Settlement

2. Pump Absorption Well 2-1. Agitator

3. Inflow pump

4. First settler distribution tank

5. First settler

6. First settling sludge pump

7. Sludge Transfer Piping

8. Sludge Distributing Adjustment Tank 8-1. agitator

9. Gravity Thickener

10. Abandonment

11. The final settler

12. Surplus activated sludge pump

13. Surplus activated sludge conveying piping

14. Mixed denitrification tank 14-1. Stirrer 14-2. Inflow piping 14-3. Outflow piping

end. Concentrated sludge pump b. Anaerobic digester Digestion sludge thickening tank

la. D. concentrated sludge pump e. Dehydrator bar. Return water piping

The present invention, in order to achieve the above technical problem, in a standard activated sludge method or a sewage / wastewater treatment plant denitrification, dephosphorization biological or chemical,

Settling paper contacting and mixing the surplus activated sludge and influent sewage transported from the final settler;

A pump absorption well and an inlet pump in which denitrification of excess activated sludge and adsorption of excess activated sludge occur while being maintained anaerobicly for a sufficient time in a mixture of excess activated sludge and sewage;

An initial settling tank in which sewage to which some organic substances are adsorbed is introduced and precipitated into the surplus activated sludge and the deactivated activated sludge in the pump absorption well;

An initial sludge pump and pipe for transferring the sludge precipitated in the initial settling tank to a gravity type thickening tank through a distribution adjusting tank;

A surplus activated sludge pump and surplus activated sludge conveying pipe for transporting surplus activated sludge to the sedimentation basin in the final settler; And

Provided is a sludge concentrating device including a distribution adjusting tank for distributing and adjusting the sludge of the initial settler and a gravity type concentrating tank for condensing the sludge.

Hereinafter, the present proposal will be described in more detail.

1 is a schematic diagram of a sludge concentrating device according to the present invention, but the following embodiments are described in detail, but the following embodiments are not limited thereto.

In the sewage treatment plant, the mixed liquid of the aeration tank 10 is separated into the supernatant and the activated sludge in the final settler 11, and most of the separated activated sludge is returned to the aeration tank (return sludge) and the remaining part is the surplus activated sludge as the surplus activated sludge. The surplus sludge transport pipe 13 was connected to the settlement 1 so that the pump 12 was transported to the settlement 1 through the surplus activated sludge transport pipe 13.

The pump absorption well (2) is connected to the rear end of the immersion paper (1), and the inlet pump (3) is installed at the end of the pump absorption well (2). It was connected to the initial settler distribution tank (4) integrally installed at the front end of.

The pump absorption well (2) was provided with a stirrer (2-1) which rotates slowly so that excess activated sludge and sewage were well mixed.

An initial settler sludge pump (6) is connected to the bottom of the initial settler (5), and the outlet pipe of this pump is connected to the sludge distribution adjusting tank (8) through the sludge conveying pipe (7) and the sludge distribution adjusting tank (8). The outlet of was connected to the gravity thickening tank (9) by piping.

The sludge concentrated in the gravity thickening tank (9) was connected to the pipe to be transferred to the anaerobic digestion tank (b) by the concentrated sludge pump (a).

The operation of the sludge concentration method and apparatus in this paper as follows.

When the mixed liquid flows from the aeration tank 10 to the final settler 11, the solids in the mixed liquid are sedimented and separated by activated sludge, and most of them are returned to the aeration tank 10 for MLSS control of the aeration tank.

The remaining activated sludge is transferred to the sedimentation basin 1 through the surplus activated sludge conveying pipe 13 by the surplus activated sludge pump 12 as surplus activated sludge, mixed with the sewage flowing into the sediment, and absorbed by the next pump. It flows into the chisel (2).

The capacity of the pump absorption well (2) typically has a residence time of at least about 1 hour with respect to the planned sewage (needs at least about 1 hour for denitrification), so that some nitrified surplus activated sludge and sewage rich in organic carbon sources When contacting, the influent sewage is anaerobic, so denitrification occurs and nitrogen gas is generated. After a certain time, denitrification is completed.

The slow absorption stirrer (2-1) is installed in the pump absorption well (2) to facilitate the contact between the surplus activated sludge and the sewage and to facilitate the divergence of gas, so that denitrification occurs well.

As such, the denitrified mixture of excess activated sludge and sewage does not generate nitrogen gas anymore, and some of the contaminants in the influent sewage are adsorbed to the surplus activated sludge by adsorption of the excess activated sludge.

When the mixture of the sewage and the surplus activated sludge is transferred to the initial settler 5, the solids are precipitated by gravity to become the initial settler sludge, and the supernatant water from which a considerable amount of contaminants are removed is transferred to the aeration tank 10 for biological treatment.

The sludge settled in the initial settler by the above-described action is very stable, and is distributed and adjusted in the sludge distribution adjusting tank 8 through the sludge conveying pipe 7 by the initial settling sludge pump 6, and thus each gravity thickening tank 9 As described above, the sludge is very stable, and as such, the sludge is very stable because there is no obstacle such as sudden gas generation during denitrification in the process of concentration in the gravity tank.

Of course, this sludge may cause gas (carbon gas) due to decay if it is stagnant for a long time in an anaerobic state, but the gas generated by this decay proceeds at a very gentle rate, so that the picket may be It is sufficiently removed by stirring only, and there is no problem in concentration.

In addition, even if the amount of surplus activated sludge increases due to a change in the operating state of the aeration tank 10, the ratio of the amount of surplus activated sludge to the total sewage inflow is about 1 to 2%. The initial settler is hydraulically stable and contains sludge which has already been denitrified in the inflow sewage, and the sludge precipitated in the first settler has little change in sludge generation and very small change in concentration of sludge. Since the sludge conveyed to the thickening tank (9) is constant with little variation in quantity and quality, the variation of the amount of excess sludge has little effect on the concentration process.

In the case of operating the thickening tank, the concentration in the thickening tank may be lowered due to seasonal or fluctuations in the inflow water quality (for example, leachate or manure inflow). If a small amount is added and concentrated after mixing with sludge, the concentration becomes high.

Another embodiment of the present invention to achieve the above object,

A mixed denitrification tank including an agitator, which is contacted, mixed and denitrated with excess activated sludge and influent sewage transferred from the final settler, and installed in the middle of the inlet pump and the initial settler distribution tank;

An initial settling tank in which the denitrification is completed and the activated activated sludge and the sewage in which some organic substances are adsorbed into the surplus activated sludge flow into and settle out;

An initial sludge pump and pipe for transferring the sludge precipitated in the initial settling tank to a gravity type thickening tank through a distribution adjusting tank;

Surplus activated sludge pump and surplus activated sludge transfer vessel to transfer surplus activated sludge to the mixed denitrification tank in the final settler; And

Provided is a sludge concentrating device including a distribution adjusting tank for distributing and adjusting the sludge of the initial settler and supplying it to the concentrating tank and a gravity type concentrating tank for concentrating the sludge.

Hereinafter, another embodiment of the present invention will be described in more detail.

In the sewage treatment plant, the mixed liquid of the aeration tank 10 is separated into the supernatant and the activated sludge in the final settler 11, and most of the separated activated sludge is returned to the aeration tank (return sludge) and the remaining part is the surplus activated sludge as the surplus activated sludge. The surplus activated sludge conveying pipe 13 was connected to the mixed denitrification tank 14 so that the pump 12 was transferred to the mixed denitrification tank 14 through the surplus activated sludge conveying pipe 13.

The pump absorption well (2) is connected to the rear end of the immersion paper (1), and the inlet pump (3) is installed at the end of the pump absorption well (2). Connected to the initial settler distribution tank (4) integrally installed at the front end of the inlet part of the outlet pipe of the inlet pump (3) is branched separately and connected to the inlet of the mixed denitrification tank (14) by the inlet pipe (14-2) The outlet side outlet pipe 14-3 of the mixed denitrification tank 14 was connected to the initial settler distribution tank 4.

The mixing denitrification tank 14 was equipped with a slow rotating stirring device 14-1, and the capacity of the mixing denitrification tank 14 was based on the maximum surplus activated sludge amount (when the operating condition was bad) and denitrification. The required amount of sewage (typically the same as the amount of surplus activated sludge) was set to 1 hour or more of the combined amount, and a plug flow (penetration flow) structure was obtained.

An initial settler sludge pump (6) is connected to the bottom of the initial settler (5), and the outlet pipe of this pump is connected to the sludge distribution adjusting tank (8) through the sludge conveying pipe (7) and the sludge distribution adjusting tank (8). The outlet of was connected to the gravity thickening tank (9) by piping.

The sludge concentrated in the gravity thickening tank (9) was connected to the pipe to be transferred to the anaerobic digestion tank (b) by the concentrated sludge pump (a).

The operation of the sludge concentration method and apparatus of another embodiment of the present invention as described above are as follows.

When the mixed liquid flows from the aeration tank 10 to the final settler 11, the solids in the mixed liquid are sedimented and separated by activated sludge, and most of them are returned to the aeration tank 10 for MLSS adjustment of the aeration tank.

The remaining part of the activated sludge is transferred to the mixed denitrification tank 14 through the surplus activated sludge conveying pipe 13 by the surplus activated sludge pump 12 as surplus activated sludge and mixed denitrification tank 14 through the inlet pump 3. It is mixed in contact with the sewage flowing into and flows into the initial settling distribution tank 4 after denitrification is completed in anaerobic state for a sufficient time.

In the case of installing the mixed denitrification tank 14, the denitrification effect cannot be expected due to the small capacity of the pump absorption well, or even if the capacity is sufficient in usual, the sewage inflow in the rainy season is rapidly increased, such as the confluence type sewage system. Effective in lack of time.

This is because even in the rainy season, only the amount of excess activated sludge and some sewage required for denitrification flows into the mixed denitrification tank 14 regardless of the amount of sewage inflow, so that the denitrification is always complete.

The slow stirring device 14-1 installed in the mixed denitrification tank 14 facilitates contact between sewage and excess activated sludge, so that denitrification occurs well and the generated nitrogen gas is well dissipated.

As such, the denitrified mixture of excess activated sludge and sewage does not generate nitrogen gas anymore, and some of the contaminants in the influent sewage are adsorbed to the surplus activated sludge by adsorption of the excess activated sludge.

In the sewage and mixed denitrification tank, the mixture of surplus activated sludge and sewage complete with denitrification is mixed together and transferred to the initial settler (5) through the initial settler distribution tank (4). The supernatant from which considerable amounts of contaminants have been removed is transferred to the aeration tank 10 for biological treatment.

The sludge settled in the initial settler by the above-described action is very stable, and is transferred from the sludge distribution adjusting tank 8 to each gravity thickening tank 9 through the sludge conveying pipe 7 by the initial settling sludge pump 6. As described above, this sludge is very stable, so it is very well concentrated because there are no obstacles such as sudden gas generation in the process.

In addition, even if the amount of surplus activated sludge increases due to a change in the operation state of the aeration tank 10, the mixed denitrification tank 14 is sufficiently denitrified due to sufficient capacity, and the mixed denitrification tank 14 even if the amount of sewage inflow increases in the rainy season. Is not affected by the rainy season because only as much sewage as needed for denitrification is introduced. After denitrification is complete, the sedimentation is separated from the initial sedimentation basin and the amount of surplus activated sludge is about 1 ~ 2% of the total sewage inflow. Since the sludge concentration change is very small and therefore the sludge amount transferred from the initial settler (5) to the gravity concentration tank (9) is almost constant, the effect of the sludge amount on the enrichment process is little and it is hydraulically stable. It can be concentrated well to produce concentrated sludge with high concentration.

In this paper, the sludge produced in sewage treatment plant or wastewater treatment plant is denitrated and stabilized regardless of the operation conditions of the aeration tank, and it is settled in the initial settler to stabilize the amount of sludge generated and the quality of sludge, and supply the sludge to the gravity thickening tank. The concentration of sludge produced can be reduced and the concentration of concentrated sludge can be increased. Therefore, the operation efficiency of the anaerobic digestion tank, which is the next process, is increased, thereby improving the sludge reduction effect, and finally reducing the amount of dehydrated cake and increasing the amount of methane gas generated. It is economical by reducing the fuel consumption from the reactor and reducing the load on the water treatment system.

Claims (2)

In sewage / wastewater treatment facilities that have advanced treatment such as standard activated sludge method or biological or chemical denitrification, Settling paper contacting and mixing the surplus activated sludge and influent sewage transported from the final settler; A pump absorption well and an inlet pump in which denitrification of excess activated sludge and adsorption of excess activated sludge occur while being maintained anaerobicly for a sufficient time in a mixture of excess activated sludge and sewage; An initial settling tank in which sewage to which some organic substances are adsorbed is introduced and precipitated into the surplus activated sludge and the deactivated activated sludge in the pump absorption well; A first sludge pump and pipe for transferring the sludge precipitated in the initial settling tank to a gravity type thickening tank through a distribution adjusting tank; A surplus activated sludge pump and surplus activated sludge conveying pipe for transporting surplus activated sludge to the sedimentation basin in the final settler; And A sludge concentrating device comprising a distribution adjusting tank for distributing and adjusting the sludge of the initial settler and a gravity concentration tank for condensing the sludge. A mixed denitrification tank including a stirring device installed in the middle of the inlet pump and the initial settler dispensing tank, in which the surplus activated sludge transferred from the final settler and the influent sewage contact, mix, and denitrate; An initial settling tank in which the denitrification is completed and the activated activated sludge and the sewage in which some organic substances are adsorbed into the surplus activated sludge flow into and settle out; An initial sludge pump and pipe for transferring the sludge precipitated in the initial settling tank to a gravity type thickening tank through a distribution adjusting tank; Surplus activated sludge pump and surplus activated sludge conveying pipe for transferring surplus activated sludge to the mixed denitrification tank in the final settler; And A sludge concentrating device comprising a distribution adjusting tank for distributing and adjusting the sludge of the initial settler and a gravity concentration tank for condensing the sludge.