WASTEWATER TREATMENT
OPERATOR FINAL PAPER
QUESTIONS SOLUTIONS
GRADED A+
The amount of time, in days, that bacteria (solids) are maintained in
the activated sludge system.
◉ What is a sludge blanket?
Settled sludge in a primary clarifier
Solids floating over a weir
Layer of solids on the bottom of the clarifier
Something an operator wears . Answer: Layer of solids on the
bottom of a clarifier
◉ How much oxygen depletion is needed for a valid BOD test?
0.5 mg/L
1.0 mg/L
, 1.5 mg/L
2.0 mg/L . Answer: 2.0 mg/L
The goal is to have at least one sample deplete by more than 2.0
mg/L oxygen and still have at least 1.0 mg/L oxygen remaining. This
is known as the 2:1 rule.
◉ The highest removal efficiencies in an RBC will occur in?
Cold weather
Warm weather
Temperature has no effect
Rainy weather . Answer: Warm weather
Bacteria activity doubles every 18°F (or 10°C).
◉ What are the predominant organisms indicative of old sludge?
Flagellates and amoebas
Rotifiers and nematodes
Stalked ciliates and free swimming cliliates
OPERATOR FINAL PAPER
QUESTIONS SOLUTIONS
GRADED A+
The amount of time, in days, that bacteria (solids) are maintained in
the activated sludge system.
◉ What is a sludge blanket?
Settled sludge in a primary clarifier
Solids floating over a weir
Layer of solids on the bottom of the clarifier
Something an operator wears . Answer: Layer of solids on the
bottom of a clarifier
◉ How much oxygen depletion is needed for a valid BOD test?
0.5 mg/L
1.0 mg/L
, 1.5 mg/L
2.0 mg/L . Answer: 2.0 mg/L
The goal is to have at least one sample deplete by more than 2.0
mg/L oxygen and still have at least 1.0 mg/L oxygen remaining. This
is known as the 2:1 rule.
◉ The highest removal efficiencies in an RBC will occur in?
Cold weather
Warm weather
Temperature has no effect
Rainy weather . Answer: Warm weather
Bacteria activity doubles every 18°F (or 10°C).
◉ What are the predominant organisms indicative of old sludge?
Flagellates and amoebas
Rotifiers and nematodes
Stalked ciliates and free swimming cliliates
