What should I do if the inclined tube sedimentation tank is often blocked? According to the secret recipe given by the factory manager, I also solved the floating of alum flowers easily.
Witten By: Jasmine
Contact Email: jasmine@juntaiplastic.com
The inclined tube sedimentation tank has the characteristics of small footprint, low cost, and high sedimentation efficiency, and is widely used in small and medium-sized water plants.
However, due to the limitations of its own structure, there are often some problems in operation, such as the floating of alum flowers, the blockage of sludge, and the outbreak of red worms.
So what should field operators do in response to these problems? In order to quickly find the root cause of the problem, and give precise strikes.
The problem of sludge accumulation in inclined tube sedimentation tank
1. The cause of sludge accumulation
A：The change of raw water causes the increase of sediment
As a result, the turbidity of the raw water entering the plant has increased; in addition, due to the continuous deterioration of the raw water quality in recent years, in addition to the continuous replacement of water purifiers, the dosage of chemicals has also increased, resulting in an increase in sediment.
B： The suction port of the suction machine is not standardized, the suction efficiency is low, and the distance from the bottom of the sedimentation tank is too large
The suction stroke cannot reach the bottom, and the sludge discharge effect is poor, so that a large amount of sludge accumulates at the bottom of the inclined tube sedimentation tank. If the suction port is long and narrow (V-shaped trapezoid), it will lead to poor flow of mud and water, easy to block, and poor suction effect.
C： There is a dead corner of scraping mud
Like other sludge scraping equipment, the suction port of the sludge discharger is at a certain distance from the side wall of the sedimentation tank. Due to the influence of the structure and equipment of the structure, the suction port cannot reach the wall, resulting in a dead corner of scraping mud and more mud at both ends of the sedimentation tank.
D：The operation mode is not reasonable, and there is no scientific adjustment according to the actual operation situation.
2. The solution to the sludge problem
A. Lower and replace the suction port
The phenomenon that the average sludge thickness at the bottom of the sedimentation tank is too large is often caused by the fact that the suction port of the sludge discharger is too far away from the bottom of the sedimentation tank, and the suction stroke cannot reach the bottom. Therefore, the height of the suction port can be lowered to a position closer to the bottom of the sedimentation tank according to the actual situation.
For example, the distance between the suction port of the original sludge discharger in a water plant is 40 cm from the bottom of the sedimentation tank, resulting in an average thickness of 70-80 cm of sludge at the bottom of the tank. The mud phenomenon is under control.
You can refer to "Sludge Discharge Machinery Part" in "Water Supply and Drainage Design Manual" to make and replace the suction port to make it in the shape of a long flat mouth, and then change the section to smoothly transition to a circular tube section to improve the suction of the suction port. Mud efficiency.
B. Reinforce the mud discharger and extend its stroke
On the one hand, reinforce the dredger rack, replace the track and wheel material of the dredger, and improve the performance of the dredger. On the other hand, the extension of the track is modified to extend the stroke of the dredger, so that when the dredger runs to the end, the suction port is closer to the edge of the foundation of the inner structural column.
C. Add inclined walls at the north and south ends of the inclined tube sedimentation tank
Due to the influence of structural columns, structural piers and the bottom frame structure of the sludge discharger at the end of the sedimentation tank, the sludge suction port of the sludge discharger cannot reach the edge of the end of the sedimentation tank, so that the mud at this place cannot be removed.
In order to solve this problem, some water plants have added high-pressure water pipes with holes at the parts at the end of the sedimentation tank that cannot be scraped by the mud suction port, so that the mud will not accumulate thick.
However, this method requires that the water pressure must be stable, controlled in a state of equal intensity and equal jet length, and the water pressure must be appropriate. Because it is under water, it is inconvenient to observe; and the flushing intensity is not easy to control. If the intensity is low, the expected effect will not be achieved, and if the intensity is high, sludge will appear.
Therefore, in the actual transformation, the method of adding inclined walls at the north and south ends of the inclined tube sedimentation tank is often adopted.
A slope is added at the end of the sedimentation tank, and the sludge accumulated on the inclined wall is drawn to the slope angle by gravity and drained with a suction machine. At the same time, in order for the mud to slide down smoothly, consider setting up smooth plastic formwork on the slope.
D. Transform the process pipeline of the sludge discharger
The siphon pipe discharges the mud, and the vacuum pump is used to form a siphon when starting. On this basis, a submersible pump is added to fill the water to form a siphon system. It has two functions: first, it is used as a backup with the vacuum pump, and prevents the phenomenon that the vacuum pump cannot start in winter; A disadvantage of flow.
D. Add time relay control device
Many sludge dischargers are designed to run to the end of the sedimentation tank and turned by the travel switch, so that there is no residence time at the end of the sedimentation tank, and the working time of sludge discharge at the end is only half of that in the middle.
Therefore, when there is a problem of sludge accumulation at both ends of the sedimentation tank, a time relay control device can be added to the control part of the sludge discharger. According to the actual sludge turbidity measurement, the sludge discharger can be stationary for a period of time when it reaches the end point before turning. There is sufficient time for sludge discharge at the end of the sedimentation tank.