Wastewater Grade 2 Study Questions
What is the methane content in a properly operating anaerobic digester?
a. 30 to 35% by volume
b. 1 to 2% by volume
c. 65 to 70% by volume
d. 15 to 20 % by volume Ans- c
What will the addition of chlorine gas do to the pH of wastewater?
a. Moderately increase the pH
b. pH will not be affected
c. Significantly increase the pH
d. Decrease the pH Ans- d
What is the purpose of a Parshall flume?
a. Measure turbidity
b. Measure flowrate
c. Measure settling rate
d. Measure solids content Ans- b
What is the typical removal efficiency of settleable solids in a primary clarifier?
a. 95 to 99%
b. 40 to 60%
C. 20 to 50%
d. 10 to 15% Ans- a
,Which of the following is true about pumping scum from a primary clarifier?
a. Pumping scum is less problematic during cold weather
b. Scum rarely leads to plugged pipelines due to its viscous nature
c. Scum causes more piping problems than other substances pumped at a wastewater treatment plant.
d. Scum causes the least amount of piping problems among all the substances pumped at a wastewater
treatment plant pumped at a wastewater treatment plant Ans- c
What might cause thick billows of white sudsy foam in the aeration tank?
a. MLSS is too high
b. Temperature in the aeration tank is too low
c. Old sludge
d. MLSS is too low Ans- d
What does the "M" in F/M ratio represent?
a. MLSS in the aeration tank
b. The influent BOD loading rate into the aeration tank
c. The mixed liquor volatile suspended solids in the aeration tank
d. The mass of inorganic solids in the aeration tank Ans- c
In general- how will warmer temperature affect the settling rate of solids in a clarifier?
a. Decrease the settling rate
b. Increase the settling rate
c. Temperature will not affect the settling rate
d. Worsens the settling rate Ans- b
,What could happen if the digester gas is mixed with air (85 TO 95% by volume)?
a. Cause an explosion
b. Improve efficiency of digestion
c. The bacteria will become aerobic and increase VSR
d. The digester becomes safer to operate due to less toxic gas in the system. Ans- a
How will algae impact the chlorine demand in the pond effluent?
a. Slightly decreases chlorine demand
b. Does not affect chlorine demand
c. Significantly decreases chlorine demand
d. Increases chlorine demand Ans- d
Which of the following is true about a positive displacement pump?
a. It is a type of centrifugal pump
b. Suction valve should be closed when the pump is started
c. It must never be started with the discharge valve closed
d. Adds head to liquid using several impellers Ans- c
What is true about the F/M ratio?
a. MLVSS data is not required to determine the F/M ratio
b. Volume of the secondary clarifier is not needed to determine the F/M ratio
c. The amount of COD or BOD entering the aeration tank does not have to be known to calculate the
F/M ratio
d. The amount of organisms in the aeration tank is not needed to calculate the F /M ratio Ans- b
, Which of the following is one of the basic rules of laboratory work?
a. Do not leave keys in equipment or vehicles at any time
b. Patrol the facilities frequently and look for suspicious activity or behavior
c. Never pipet hazardous material with your mouth even if the pi pet has been sterilized
d. Lock out and tag out relevant mechanical and electrical equipment before starting any maintenance
activity Ans- c
What is the recirculation ratio for a trickling filter?
a. Qr/Q
b. Q/Qr
c. Q/ Qr+Q
d. Qr+Q/Q Ans- a
Which of the following is true about COD and BOD?
a. They are direct measurements of the organic content in the influent
b. They measure the inorganic content of the influent
c. They represent the amount of filamentous bacteria in the influent
d. They are indirect measurements of the organic content in the influent Ans- d
What is the purpose of the grit channel?
a. Remove dissolved and non-settleable organics
b. Remove heavy inorganic wastes.
c. To allow activated sludge to settle
What is the methane content in a properly operating anaerobic digester?
a. 30 to 35% by volume
b. 1 to 2% by volume
c. 65 to 70% by volume
d. 15 to 20 % by volume Ans- c
What will the addition of chlorine gas do to the pH of wastewater?
a. Moderately increase the pH
b. pH will not be affected
c. Significantly increase the pH
d. Decrease the pH Ans- d
What is the purpose of a Parshall flume?
a. Measure turbidity
b. Measure flowrate
c. Measure settling rate
d. Measure solids content Ans- b
What is the typical removal efficiency of settleable solids in a primary clarifier?
a. 95 to 99%
b. 40 to 60%
C. 20 to 50%
d. 10 to 15% Ans- a
,Which of the following is true about pumping scum from a primary clarifier?
a. Pumping scum is less problematic during cold weather
b. Scum rarely leads to plugged pipelines due to its viscous nature
c. Scum causes more piping problems than other substances pumped at a wastewater treatment plant.
d. Scum causes the least amount of piping problems among all the substances pumped at a wastewater
treatment plant pumped at a wastewater treatment plant Ans- c
What might cause thick billows of white sudsy foam in the aeration tank?
a. MLSS is too high
b. Temperature in the aeration tank is too low
c. Old sludge
d. MLSS is too low Ans- d
What does the "M" in F/M ratio represent?
a. MLSS in the aeration tank
b. The influent BOD loading rate into the aeration tank
c. The mixed liquor volatile suspended solids in the aeration tank
d. The mass of inorganic solids in the aeration tank Ans- c
In general- how will warmer temperature affect the settling rate of solids in a clarifier?
a. Decrease the settling rate
b. Increase the settling rate
c. Temperature will not affect the settling rate
d. Worsens the settling rate Ans- b
,What could happen if the digester gas is mixed with air (85 TO 95% by volume)?
a. Cause an explosion
b. Improve efficiency of digestion
c. The bacteria will become aerobic and increase VSR
d. The digester becomes safer to operate due to less toxic gas in the system. Ans- a
How will algae impact the chlorine demand in the pond effluent?
a. Slightly decreases chlorine demand
b. Does not affect chlorine demand
c. Significantly decreases chlorine demand
d. Increases chlorine demand Ans- d
Which of the following is true about a positive displacement pump?
a. It is a type of centrifugal pump
b. Suction valve should be closed when the pump is started
c. It must never be started with the discharge valve closed
d. Adds head to liquid using several impellers Ans- c
What is true about the F/M ratio?
a. MLVSS data is not required to determine the F/M ratio
b. Volume of the secondary clarifier is not needed to determine the F/M ratio
c. The amount of COD or BOD entering the aeration tank does not have to be known to calculate the
F/M ratio
d. The amount of organisms in the aeration tank is not needed to calculate the F /M ratio Ans- b
, Which of the following is one of the basic rules of laboratory work?
a. Do not leave keys in equipment or vehicles at any time
b. Patrol the facilities frequently and look for suspicious activity or behavior
c. Never pipet hazardous material with your mouth even if the pi pet has been sterilized
d. Lock out and tag out relevant mechanical and electrical equipment before starting any maintenance
activity Ans- c
What is the recirculation ratio for a trickling filter?
a. Qr/Q
b. Q/Qr
c. Q/ Qr+Q
d. Qr+Q/Q Ans- a
Which of the following is true about COD and BOD?
a. They are direct measurements of the organic content in the influent
b. They measure the inorganic content of the influent
c. They represent the amount of filamentous bacteria in the influent
d. They are indirect measurements of the organic content in the influent Ans- d
What is the purpose of the grit channel?
a. Remove dissolved and non-settleable organics
b. Remove heavy inorganic wastes.
c. To allow activated sludge to settle
