Review questions

  1. The two types of RBC drives are ______________ and ___________.
  2. The term used to describe uneven shaft rotations is
    1. Loping
    2. Sloughing
    3. Trickling
    4. Drumming
  3. The highest removal efficiencies in an RBC will occur in
    1. Cold weather
    2. Warm weather
    3. Temperature has no effect
    4. None of the above
  4. RBC’s rotate at about _____ rpm with around _____% of the media submerged.
    1. 40, 1.5
    2. 1.5, 40
    3. 4.5, 10
    4. 10, 4.5
  5. What is the hydraulic loading rate of a 4 stage RBC system with an influent flow of 350,000 gpd and 45,000 ft2 per stage?
    1. 77.8 gpd/ft2
    2. 7.78 gpd/ft2
    3. 19.4 gpd/ft2
    4. 1.94 gpd/ft2
  6. Like trickling filters, RBC’s are a
    1. Suspended growth process
    2. Biological process
    3. Anaerobic process
    4. None of the above
  7. Solids build up in the reactor basin can cause
    1. Reduced detention times
    2. Anaerobic conditions
    3. Drum rotation to stop
    4. All of the above
  8. Adjusting the rotation speed of the drum, changing the recirculation rate, and step feeding the influent are all methods of
    1. Controlling the organic loading
    2. Determining the condition of the media
    3. Checking for short circuiting
    4. Controlling the dissolved oxygen level
  9. The effluent from RBC’s usually flows to a primary clarifier.
    1. True
    2. False
  10. Calculate the organic loading (lbs.BOD/day/1000 ft2) of an RBC with the following data.