Ca Grade 2 Wastewater Treatment Operator Practice Exam
1| 80 questions| with complete solutions
What is the methane content in a properly operating anaerobic digester? Correct Answer: 65 to
70% by volume
What will the addition of chlorine gas do to the pH of wastewater? Correct Answer: decrease the
pH
What is the purpose of a Parshall Flume? Correct Answer: Measure the flow rate
What is the typical removal efficency of settleable solids in a primary clarifier? Correct Answer:
95 to 99%
Which of the follwing is true about pumoing scum from a primary clarifier? Correct Answer:
scum causes more piping problems than other substances pumped at a wastewater treatment
plant
What might cause thick billows of white sudsy foam in the aeration tank? Correct Answer:
MLSS is too low
What does the M in F/M ratio represent? Correct Answer: The mixed liquor volatile suspended
solids in the aeration tank
In general, how will warmer temp affect the settling rate of solids in a clarifer? Correct Answer:
Increase the settling rate
What could happen if the digester gas is mixed with air(85 to 95% by volume)? Correct Answer:
Cause an explosion
How will algae impact the chlorine demand in the pond effluent? Correct Answer: increase the
chlorine demand
Which of the following is true about a positive displacement pump? Correct Answer: it must
never be started with the discharge valve closed
What is true about the F/M ratio? Correct Answer: the volume of the secondary clarifier is not
needed to determine the f/m ratio
Which of the following is one of the basic rules of lab work? Correct Answer: never pipet
hazardous material with your mouth, even if the pipet has been sterialized
What is the recirculation ratio for a trickling filter? Correct Answer: Qr/Q
, Which of the following is true about COD and BOD? Correct Answer: they are indirect
measurements of the organic content in the influent
What is the purpose of the grit channel? Correct Answer: remove heavy inorganic waste
Which of the following is true about the extended aeration process? Correct Answer: it does not
produce as much waste sludge as other processes
What is the correct formula for solids in raw wastewater? Correct Answer: Non settleable solids
+ settleable solids = total suspended solids
What is freeboard in a waste stabilization pond? Correct Answer: the vertical distance from
normal water surface to the top of the levee
What is one of the requirements for a BOD test? Correct Answer: The BOD bottle should be
completely filled to the top
What should be scheduled every 3 months for a flamer arrester in an anaerobic digester? Correct
Answer: maintenance
What is common practice in an activated sludge process? Correct Answer: recirculate activated
sludge
Prior to entering a permit-required confined space, what should you verify? Correct Answer: a
standby person should be located outside the entrance to the confined space, while another
person should be within sight or call of the standby person
What is a common way to determine the organic strength of wastes in the influent? Correct
Answer: test for the biochemical oxygen demand
What should you do if you are mildly exposed to chlorine gas? Correct Answer: immediately
evacuate the contaminated area, remian calm, keep warm. breath lightly, avoid coughing
What are the main sources of domestic sewage in the collection system? Correct Answer:
household and commercial establishments
Why is it important to maintain a horizontal weir in a clarifier? Correct Answer: to prevent short
circuiting
What are mostly removed in the grit channel? Correct Answer: sand, eggshells, cinders, and
heavier particulate matter
How often should an anaerobic digester be fed? Correct Answer: several times a day
What is the health effect of carbon dioxide? Correct Answer: could lead to asphyxiation
1| 80 questions| with complete solutions
What is the methane content in a properly operating anaerobic digester? Correct Answer: 65 to
70% by volume
What will the addition of chlorine gas do to the pH of wastewater? Correct Answer: decrease the
pH
What is the purpose of a Parshall Flume? Correct Answer: Measure the flow rate
What is the typical removal efficency of settleable solids in a primary clarifier? Correct Answer:
95 to 99%
Which of the follwing is true about pumoing scum from a primary clarifier? Correct Answer:
scum causes more piping problems than other substances pumped at a wastewater treatment
plant
What might cause thick billows of white sudsy foam in the aeration tank? Correct Answer:
MLSS is too low
What does the M in F/M ratio represent? Correct Answer: The mixed liquor volatile suspended
solids in the aeration tank
In general, how will warmer temp affect the settling rate of solids in a clarifer? Correct Answer:
Increase the settling rate
What could happen if the digester gas is mixed with air(85 to 95% by volume)? Correct Answer:
Cause an explosion
How will algae impact the chlorine demand in the pond effluent? Correct Answer: increase the
chlorine demand
Which of the following is true about a positive displacement pump? Correct Answer: it must
never be started with the discharge valve closed
What is true about the F/M ratio? Correct Answer: the volume of the secondary clarifier is not
needed to determine the f/m ratio
Which of the following is one of the basic rules of lab work? Correct Answer: never pipet
hazardous material with your mouth, even if the pipet has been sterialized
What is the recirculation ratio for a trickling filter? Correct Answer: Qr/Q
, Which of the following is true about COD and BOD? Correct Answer: they are indirect
measurements of the organic content in the influent
What is the purpose of the grit channel? Correct Answer: remove heavy inorganic waste
Which of the following is true about the extended aeration process? Correct Answer: it does not
produce as much waste sludge as other processes
What is the correct formula for solids in raw wastewater? Correct Answer: Non settleable solids
+ settleable solids = total suspended solids
What is freeboard in a waste stabilization pond? Correct Answer: the vertical distance from
normal water surface to the top of the levee
What is one of the requirements for a BOD test? Correct Answer: The BOD bottle should be
completely filled to the top
What should be scheduled every 3 months for a flamer arrester in an anaerobic digester? Correct
Answer: maintenance
What is common practice in an activated sludge process? Correct Answer: recirculate activated
sludge
Prior to entering a permit-required confined space, what should you verify? Correct Answer: a
standby person should be located outside the entrance to the confined space, while another
person should be within sight or call of the standby person
What is a common way to determine the organic strength of wastes in the influent? Correct
Answer: test for the biochemical oxygen demand
What should you do if you are mildly exposed to chlorine gas? Correct Answer: immediately
evacuate the contaminated area, remian calm, keep warm. breath lightly, avoid coughing
What are the main sources of domestic sewage in the collection system? Correct Answer:
household and commercial establishments
Why is it important to maintain a horizontal weir in a clarifier? Correct Answer: to prevent short
circuiting
What are mostly removed in the grit channel? Correct Answer: sand, eggshells, cinders, and
heavier particulate matter
How often should an anaerobic digester be fed? Correct Answer: several times a day
What is the health effect of carbon dioxide? Correct Answer: could lead to asphyxiation
