GATE CE 2022: Environmental Engineering Quiz #7

Match list-I with list-II and select the correct answer using the codes given below the lists:

A rectangular tank 18 m x 8 m x 4m of water depth treats 4 million litres of water per day. The detention time for tank will be ____hours.

Calculate the plan area of a grit chamber to remove particles of diameter 0.2 mm and specific gravity is 2.7. Settling velocity of the particle is 0.017 m/s. The proportioning weir will be having a velocity of 0.3 m/sec. The maximum wastewater flow is expected to be 1200 m³/day. Assume depth of 1 m and additional length for turbulence is also considered.

A completely mix process is designed with the following data:

Q₀ = 10000 m³/d, BOD after PST = 150 mg/l, effluent BOD = 5 mg/l

Y = 0.5 kg/kg, K_d = 0.05 per day, MLSS = 3000 mg/l

Underflow concentration (Xu) = 10000 mg/l for 2° sedimentation tank, θ_c = 8 days. What should be the reactor volume in m³?

The sewage is flowing at the rate of 4.7 million litres per day from a primary clarifier to a standard rate trickling filter. The BOD of the influent is 150 mg/l. The organic loading rate is 160 gm/m³/day and surface loading rate is 2000 l/m²/day. Calculate the depth of the filter in meter.