WATR 081 Spring 2022 Module 5 Assessment Quiz PDF

WATR 081 - Spring 2022 Module 5 Assessment Quiz Shabbir Basrai 1. A well-operated primary clarier, will remove between 90 and 95 percent of the inuent settleable solids. a. True b. False 2. Operators may use sludge blanket levels in primary clariers to adjust sludge pumping rates. a. True b. F...

WATR 081 - Spring 2022 Module 5 Assessment Quiz Shabbir Basrai 1. A well-operated primary clarier, will remove between 90 and 95 percent of the inuent settleable solids. a. True b. False 2. Operators may use sludge blanket levels in primary clariers to adjust sludge pumping rates. a. True b. False 3. Baes ahead of outlet weirs in primary tanks serve as a physical barrier to inhibit the loss of oating solids and grease. a. True b. False 4. A primary clarier does not have adequate detention time. Which of the following would result? a. Decreased organic leading on secondary unit b. Overloading of collector or ight drive motor c. Increased solids pumped to digester d. Low BOD removal e. Reduced suspended solids in aeration tank. 5. If the sludge depth in a secondary sedimentation tank is too high, what will happen? a. Decreased turbidity in euent. b. Return activated sludge will have lower oxygen demand c. Settleable solids from aeration tank will increase d. Sludge may become septic 6. At a 2.5 MGD wastewater treatment plant the primary clarier has a detention time of 2 hours. How many gallons does this clarier hold? Page 1 of 2 Module 5 Assessment Quiz Shabbir Basrai Answers: 1. a. 2. a. 3. a. 5. d. 6. At a 2.5 MGD wastewater treatment plant the primary clarier has a detention time of 2 hours. How many gallons does this clarier hold? Solution: Clarif ier detention time (hr) = Clarif ier volume(gal) Inf luent f low (gal/hr) =⇒ Clarif ier volume(gal) = Clarif ier detention time (hr) ∗ Inf luent f low (gal/hr) =⇒ Clarif ier volume(gal) = 2hrs ∗ 2, 500, 000 Page 2 of 2 gal day ∗ = 208, 333gal day 24 hrs WATR 081 - Spring 2022