STUDY GUIDE 2026 WITH ACTUAL QUESTIONS
AND VERIFIED CORRECT ANSWERS GRADED
A+
◉Mean Cell Residence Time (MCRT) . Answer: The amount of time, in
days, that bacteria (solids) are maintained in the activated sludge system.
◉What is a sludge blanket? . Answer: Layers of solids on the bottom of
the clarifier.
◉How much oxygen depletion is needed for a valid BOD test? .
Answer: 2.0 mg/L
◉The highest removal efficiencies in an RBC will occur in?
a) cold weather
b) warm weather
c) temperature has no effect
d) rainy weather . Answer: b) warm weather
(bacteria activity double every 18 degree F)