A water treatment plant is treating 5.0 MGD (18.9 MLD) of water. The raw water has a suspended solids concentration of 300 mg/L, composed of particles having a diameter of XXXXXXXXXXcm and specific...

A water treatment plant is treating 5.0 MGD (18.9 MLD) of water. The raw water has a suspended solids concentration of 300 mg/L, composed of particles having a diameter of 0.0015 cm and specific gravity of 2.20. The plant has four sedimentation tanks. Each tank is 80 ft (24.38 m) long, 25 ft (7.62 m) wide, and 8 ft (2.44 m) deep (all are water working dimensions). Assume 𝜈 of water is 1.12 × 10−2 cm2/s

(a) What will be the detention time for sedimentation? (h)

(b) What will be the overflow rate of the tanks? (gal/ft²/d or m³/d/m²)

(c) What is the % solids removal or settling efficiency of the plant? (%)

(d) What is the actual velocity of a solid particle in the tanks? (cm/s)