Tube settlers and parallel ...

Tube settlers and parallel plates increase the settling capacity of circular clarifiers and/or rectangular sedimentation basins by reducing the vertical distance a floc particle must settle before agglomerating to form larger particles

Tube settlers are based on different theory that states that settling is dependent on settling area rather than detention time. Keep the angle of inclination of Tubes between 45 degree and 60 degree. Since above 60 degree angle will cause them to be ineffective and below 45 degree angle will cause choking problems.
The equations for settling is simply derived from time- distance-speed relationship, which further calculates the distance required to settle the particle with specific settling velocity.Solids loading are less (as in case of municipal wastewaters of industries with low sludge post treatments (less inert TSS in inlet and less yield). These have a hydraulic radius of 80 mm or even 60 mm for hexagonal chevron model which keeps the velocity of settling low through pipes and thus the Reynold's number.

When we are to handle large quantity of sludges we work with lamella plates spaces about 100 mm apart (spacing can even be different based on requirements and quantity of sludges generated). 

Since the water is supplied through small channels the fluid attains least turbulence and thus keeps the control over flow pattern.

Advantages of Tube Settlers

The advantages of tube settlers can be applied to new or existing clarifiers/basins of any size:

1. Clarifiers/basins equipped with tube settlers can operate at 2 to 4 times the normal rate of clarifiers/basins without tube settlers.
2. It is possible to cut coagulant dosage by up to half while maintaining a lower influent turbidity to the treatment plant filters.
3. Less filter backwashing equates to significant operating cost savings for both water and electricity.
4. New installations using tube settlers can be designed smaller because of increased flow capability.
5. Flow of existing water treatment plants can be increased through the addition of tube settlers.
6. Tube settlers increase allowable flow capacity by expanding settling capacity and increasing the solids removal rate in settling tanks.

Tube settlers increase the settling capacity of circular clarifiers and/or rectangular sedimentation basins by reducing the vertical distance a flock particle has to travel downwards for settling or to agglomerate to form larger particles.

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