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CA GRADE 2 WASTEWATER TREATMENT
OPERATOR PRACTICE EXAM 1 QUESTIONS
WITH SOLUTIONS
What is the methane content in a properly operating anaerobic digester? -
correct-answer-65 to 70% by volume
What must you do before entering a room with harmful concentration of chlorine
gas in the air? - correct-answer-wear self contained breathing apparatus(scba)
What does black sludge at the bottom of a secondary clarifier located
downstream of a trickling filter signify? - correct-answer-sludge has stayed in the
secondary clarifier too long
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If the lab results show that the plant influent sample has COD of 100 mg/l and a
BOD of 300 mg/l, which of the following is most likey true? - correct-answer-lab
results appear incorrect
If a primary clarifier is placed out of service, then how should a plant with at least
2 trickling filters operate the system? - correct-answer-operate the filters in series
What is the main reason for preventing a direct connection between a potable
water pipe and a stuffing box(packings) of a wastewater pump? - correct-answer-
cross connection
Which of the following is true about algae in a pond? - correct-answer-during the
day time the algae will release oxygen for the aerobic bacteria in the pond
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Which of the following is not true about hydrogen sulfide? - correct-answer-
hydrogen sulfide is lighter than air
What type of treatment is primarily used to thicken sludge instead of dewater the
sludge? - correct-answer-DAF Dissolved Air Flotation
Why should sludge at the bottom of a clarifier be removed in a timely manner? -
correct-answer-to prevent sludge gasification which causes the sludge to float
What is the purpose of sludge digestion? - correct-answer-reduce the volume of
the sludge and stabilize the solids
Which of the following is true about truckling filters? - correct-answer-the three
main parts of a trickling filter are media, distribution system, and underdrain
CA GRADE 2 WASTEWATER TREATMENT
OPERATOR PRACTICE EXAM 1 QUESTIONS
WITH SOLUTIONS
What is the methane content in a properly operating anaerobic digester? -
correct-answer-65 to 70% by volume
What must you do before entering a room with harmful concentration of chlorine
gas in the air? - correct-answer-wear self contained breathing apparatus(scba)
What does black sludge at the bottom of a secondary clarifier located
downstream of a trickling filter signify? - correct-answer-sludge has stayed in the
secondary clarifier too long
,2|Page
If the lab results show that the plant influent sample has COD of 100 mg/l and a
BOD of 300 mg/l, which of the following is most likey true? - correct-answer-lab
results appear incorrect
If a primary clarifier is placed out of service, then how should a plant with at least
2 trickling filters operate the system? - correct-answer-operate the filters in series
What is the main reason for preventing a direct connection between a potable
water pipe and a stuffing box(packings) of a wastewater pump? - correct-answer-
cross connection
Which of the following is true about algae in a pond? - correct-answer-during the
day time the algae will release oxygen for the aerobic bacteria in the pond
, 3|Page
Which of the following is not true about hydrogen sulfide? - correct-answer-
hydrogen sulfide is lighter than air
What type of treatment is primarily used to thicken sludge instead of dewater the
sludge? - correct-answer-DAF Dissolved Air Flotation
Why should sludge at the bottom of a clarifier be removed in a timely manner? -
correct-answer-to prevent sludge gasification which causes the sludge to float
What is the purpose of sludge digestion? - correct-answer-reduce the volume of
the sludge and stabilize the solids
Which of the following is true about truckling filters? - correct-answer-the three
main parts of a trickling filter are media, distribution system, and underdrain
