Grade 2 Wastewater Treatment Operator
Practice Exam Q&A 2024/2025
What is the methane content in a properly operating anaerobic digester?
65 to 70% by volume
What will the addition of chlorine gas do to the pH of wastewater?
decrease the pH
What is the purpose of a Parshall Flume?
Measure the flow rate
What is the typical removal efficency of settleable solids in a primary clarifier?
95 to 99%
Which of the follwing is true about pumoing scum from a primary clarifier?
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?
MLSS is too low
What does the M in F/M ratio represent?
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?
Increase the settling rate
What could happen if the digester gas is mixed with air(85 to 95% by volume)?
Cause an explosion
How will algae impact the chlorine demand in the pond effluent?
increase the chlorine demand
Which of the following is true about a positive displacement pump?
it must never be started with the discharge valve closed
What is true about the F/M ratio?
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?
never pipet hazardous material with your mouth, even if the pipet has been sterialized
What is the recirculation ratio for a trickling filter?
Qr/Q
, Which of the following is true about COD and BOD?
they are indirect measurements of the organic content in the influent
What is the purpose of the grit channel?
remove heavy inorganic waste
Which of the following is true about the extended aeration process?
it does not produce as much waste sludge as other processes
What is the correct formula for solids in raw wastewater?
Non settleable solids + settleable solids = total suspended solids
What is freeboard in a waste stabilization pond?
the vertical distance from normal water surface to the top of the levee
What is one of the requirements for a BOD test?
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?
maintenance
What is common practice in an activated sludge process?
recirculate activated sludge
Prior to entering a permit-required confined space, what should you verify?
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?
test for the biochemical oxygen demand
What should you do if you are mildly exposed to chlorine gas?
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?
household and commercial establishments
Why is it important to maintain a horizontal weir in a clarifier?
to prevent short circuiting
What are mostly removed in the grit channel?
sand, eggshells, cinders, and heavier particulate matter
Practice Exam Q&A 2024/2025
What is the methane content in a properly operating anaerobic digester?
65 to 70% by volume
What will the addition of chlorine gas do to the pH of wastewater?
decrease the pH
What is the purpose of a Parshall Flume?
Measure the flow rate
What is the typical removal efficency of settleable solids in a primary clarifier?
95 to 99%
Which of the follwing is true about pumoing scum from a primary clarifier?
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?
MLSS is too low
What does the M in F/M ratio represent?
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?
Increase the settling rate
What could happen if the digester gas is mixed with air(85 to 95% by volume)?
Cause an explosion
How will algae impact the chlorine demand in the pond effluent?
increase the chlorine demand
Which of the following is true about a positive displacement pump?
it must never be started with the discharge valve closed
What is true about the F/M ratio?
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?
never pipet hazardous material with your mouth, even if the pipet has been sterialized
What is the recirculation ratio for a trickling filter?
Qr/Q
, Which of the following is true about COD and BOD?
they are indirect measurements of the organic content in the influent
What is the purpose of the grit channel?
remove heavy inorganic waste
Which of the following is true about the extended aeration process?
it does not produce as much waste sludge as other processes
What is the correct formula for solids in raw wastewater?
Non settleable solids + settleable solids = total suspended solids
What is freeboard in a waste stabilization pond?
the vertical distance from normal water surface to the top of the levee
What is one of the requirements for a BOD test?
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?
maintenance
What is common practice in an activated sludge process?
recirculate activated sludge
Prior to entering a permit-required confined space, what should you verify?
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?
test for the biochemical oxygen demand
What should you do if you are mildly exposed to chlorine gas?
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?
household and commercial establishments
Why is it important to maintain a horizontal weir in a clarifier?
to prevent short circuiting
What are mostly removed in the grit channel?
sand, eggshells, cinders, and heavier particulate matter
