PRACTICE PROBLEMS 9.1: Detention Time 1. A circular clarifier has a capacity of 150,000 gallons. If the flow through the clarifier is 1,720,000 gpd, what is the detention time in hours for the clarifier? (Round to the nearest tenth.) ANS _ 2. The flow to a sedimentation tank 80 ft long, 20 ft wide, and 12 ft deep is 3.15 MOD. What is the detention time in the tank, in hours? (Round to the nearest tenth.) ANS _ 3. A circular clarifier receives a flow of 4,340,000 gpd. If the clarifier is 80 ft in diameter and 12 ft deep, what is the clarifier detention time in hours? Assume the flow is steady and continuous. (Round to the nearest tenth.) 4. The flow to a sedimentation tank 70 ft long, 30 ft wide, and 12 ft deep is 3.12 MGD. What is the detention time in hours in the tank? (Round to the nearest tenth.) ANS _ PRACTICE PROBLEMS 9.2: Weir Overflow Rate 1. A rectangular clarifier has a total of 110 ft of weir. What is the weir overflow rate in gpd/ft when the flow is 1,463,000 gpd? ANS _ 2. A circular clarifier receives a flow of