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Sedimentation tank exit channel
Josiah, Taisuk, Jeff 6/30/09
The sedimentation tank exit channel is currently a replicate of the entrance channel. The entrance channel size is based on the constraint of not breaking up flocs. This constraint causes the exit channel to be much larger than is necessary. The exit channel should be designed based on the constraint that the head loss in the open channel must be very small compared with the head loss in the launder orifices. This constraint ensures that the flow is uniformly distributed between sedimentation tank bays. The most sophisticated solution algorithm could use the direct step method and incorporate the changing flow through the channel. A simpler solution that would be conservative would be a simple friction slope calculation using the Darcy Weisbach equation adopted for flow in a rectangular channel. The friction slope times the length of the channel can be compared with the head loss in the orifices.
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