A colleague asks you to check their design of a settling bas

A colleague asks you to check their design of a settling basin for alum flocs. Which of the following design parameters would you question because it is outside of the typical range?

a)

Overflow Rate: 550 gpd/ft^2

b)

Weir Loading Rate: 14,000 gpd/ft

c)

Hydraulic Residence Time: 1.2 hours

d)

Circular Tank Depth: 15 ft

Solution

c) hydraulic residence time: 1.2 hours (It does not match with actual range)

(actual range: 4-6 hours)