Question

A single primary clarifier is being designed for a new 3 MGD wastewater treatment plant. The clarifier is being designed with an overflow rate of 1,000 gal/day-ft?, a depth of 12 ft, and a length of 100 ft. Determine the width of the primary clarifier. 20 ft 30 ft 40 ft 50 ft

Answer 1

Here we have,

Rate of flow,Q = 3 MGD = 3×10⁶ gal/day

Overflow rate,OFR = 1000 gal/day-ft²

Depth of clarifier,D = 12 ft

Length of clarifier,L = 100 ft.

Now Required area of clarifier is given by,

$\small A_{req}=\frac{Q}{OFR} = \frac{3*10^6 \frac{gal}{day}}{1000 \frac{gal}{day-ft^2}}$

Area = 3000 ft

As we have the length of clarifier equal to 100 ft,thus

$\small Width=\frac{A_{req}}{L}=\frac{3000\ ft^2}{100\ ft}=30 \ ft$

Thus width of clarifier is 30 feet.