Sedimentation and Other Clarification Processes - Public Water Systems - page 313

TABLE 11-3. Common Weir Overflow Rates

Weir Overflow Rate

Type of Floc gpm/ft m 3 /h/m

Alum floc, low-turbidity water 8-10 5.9-7.4

Alum floc, high-turbidity water 10-15 7.4-11.2

Lime-softening floc 15-18 11.2-13.4

(From Culp, Gordon, and Williams, Robert, Handbook of Public Water Systems. Copyright 1986 by John

Wiley & Sons, Inc. Reprinted by permission of John Wiley & Sons, Inc.)

A. Flow Pattern in Conventional Circular Clarifier

B. Flow Pattern in Baffled Circular Clarifier

Weir Plate

Scum Baffle

610 mm

C. Clarifier Baffle at Weir Trough

Fig. 11-6. Circular clarifier, flow patterns resulting from baffling (From Culp, Gordon, and Wil-
liams, Robert, Handbook of Public Water Systems. Copyright 1986 by John Wiley & Sons,
Inc. Reprinted by permission of John Wiley & Sons, Inc.)