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M&M I-Practice Final Clarifier Math

 

The flow through an activated sludge plant is 15 mgd.  The BOD of the primary effluent is 110 mg/L and the BOD of the final effluent is 8 mg/L.  The MLSS is the aeration tank is 2,500 mg/L.  The 30-minute settleable solids test is 225 mL/L.  The TSS of the primary effluent is 115 mg/L and the TSS of the final effluent is 12 mg/L.  The return sludge ratio is 20%.  60,000 gallons of 2% sludge are wasted each day.  The flow is split evenly between two equal-sized rectangular aeration tanks and final clarifiers.  Each aeration tank is 175 feet long, 75 feet wide, and 12 feet deep.  Each final clarifier has a 75 feet diameter, a SWD of 8 feet, and they are 12 feet deep in the center.

  1. The circumference of a final clarifier is ________ feet.

 

 

  1. The surface area of a final clarifier is ________ square feet.

 

 

  1. The volume of a final clarifier is ________ cubic feet.

 

 

  1. A final clarifier holds  ______ gallons.

 

 

  1. The detention time of a final clarifier is _______ minutes.

 

 

  1. The detention time of a final clarifier is _______ hours.

 

 

  1. The surface settling rate of a final clarifier is _______ gpd/square foot

 

 

  1. The weir overflow rate of a final clarifier is ________ gpd/ft

 

 

  1. The solids loading rate of a final clarifier is ________ lbs/day/sq ft

 

 

  1. The BOD removed is ______ mg/L.

 

 

  1. The BOD removed is ______ lbs/day.

 

 

  1. The BOD discharged by the plant is ______ lbs/day.

 

 

  1. The TSS removed is ______ mg/L.

 

 

  1. The TSS removed is ______ lbs/day.

 

 

  1. The TSS discharged by the plant is ______ lbs/day.

 

 

  1. The BOD removal efficiency is _____ %.

 

 

  1. The TSS removal efficiency is _____ %.

 

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