What flow rate does the 60 ft diameter clarifier treat in the example?

What flow rate does the 60 ft diameter clarifier treat in the example?

• A. 3,000 gpm
• B. 2,000 gpm
• C. 1,000 gpm
• D. 4,000 gpm

Answer: (B)

Calculating a circular clarifier’s flow uses its surface area and the allowed surface overflow rate. For a 60 ft diameter, the area is πr^2 = π×(30)^2 = 900π ft^2 ≈ 2,827 ft^2. Using a typical design overflow rate of about 1,000 gpd per square foot, the daily flow capacity would be 2,827×1,000 ≈ 2.83×10^6 gpd. Converting to gpm: 2.83×10^6 gpd ÷ 1,440 ≈ 1,963 gpm, which is about 2,000 gpm. So the example treats roughly 2,000 gpm.

Calculating a circular clarifier’s flow uses its surface area and the allowed surface overflow rate. For a 60 ft diameter, the area is πr^2 = π×(30)^2 = 900π ft^2 ≈ 2,827 ft^2. Using a typical design overflow rate of about 1,000 gpd per square foot, the daily flow capacity would be 2,827×1,000 ≈ 2.83×10^6 gpd. Converting to gpm: 2.83×10^6 gpd ÷ 1,440 ≈ 1,963 gpm, which is about 2,000 gpm. So the example treats roughly 2,000 gpm.