WASTEWATER PRACTICE EXAM 4 MOCK TEST
WITH ANSWER RATIONALES 2026
◉ light brown and frothy.
Answer: Healthy mixed liquor in an activated sludge process should
have what appearance?
◉ there is a problem with the bearing lubrication and connection.
Answer: What does a gradual increase in the bearing temperature of
a centrifugal blower indicate?
◉ detention time.
Answer: The time is takes for a unit volume of wastewater to pass
entirely through a primary clarifier is called
◉ centrifugal.
Answer: Pumps are often required to bring wastewater into a
treatment plant. What types of pumps are typically used to lift
influent wastewater?
◉ typhoid fever, dysentery, cholera.
Answer: Three waterborne diseases are
,◉ 2-5 mg/L.
Answer: Conventional activated sludge systems typically operate
with a DO range of:
◉ SDS.
Answer: Which of the following provides safety information for
potentially hazardous or toxic materials?
◉ alert the operator on duty.
Answer: The first step the maintenance staff should take in properly
locking and tagging out a piece of equipment is to:
◉ Denitrification.
Answer: Which of the following would NOT be considered
preliminary treatment?
◉ 19.5%.
Answer: Oxygen deficiency becomes a concern when the oxygen
level in a confined space is less than
◉ Air Lift.
,Answer: This type of pump injects compressed air into a discharge
line, which mixes and raises solids through the line due to sludge
density.
◉ Nitrification.
Answer: The appearance of duckweed in a final clarifier is an
indication of:
◉ Packing.
Answer: This material can be made from Teflon or graphite and is
used to prevent leakage between moving parts of a pump:
◉ make no adjustment.
Answer: What is the first course of action if you see a slow constant
drip from a pump shaft packing seal?
◉ mixed liquor volatile suspended solids.
Answer: Which of the following types of solids most accurately
represent the microorganisms in the activated sludge process?
◉ none, it must analyzed immediately.
Answer: What is the maximum recommended holding time for a
sample that is to be analyzed for pH?
, ◉ Reciprocating.
Answer: This type of positive displacement pump consists of a
piston that moves back and forth
◉ sodium sulfite solution.
Answer: Most DO probes come with an electronic zero for
calibration. What should be used to check the accuracy of this
feature on a DO probe?
◉ secured together.
Answer: When working in an area with two or more floor coverings
(for example, grating and checker-plate), be sure that they are
always
◉ Hydrogen sulfide.
Answer: A rotten egg smell in wastewater can most likely be
attributed to:
◉ an area where conditions are very calm and no mixing is taking
place.
Answer: A "dead" spot in an activated sludge biological reactor is
typically identified visually as
◉ bacteria.
WITH ANSWER RATIONALES 2026
◉ light brown and frothy.
Answer: Healthy mixed liquor in an activated sludge process should
have what appearance?
◉ there is a problem with the bearing lubrication and connection.
Answer: What does a gradual increase in the bearing temperature of
a centrifugal blower indicate?
◉ detention time.
Answer: The time is takes for a unit volume of wastewater to pass
entirely through a primary clarifier is called
◉ centrifugal.
Answer: Pumps are often required to bring wastewater into a
treatment plant. What types of pumps are typically used to lift
influent wastewater?
◉ typhoid fever, dysentery, cholera.
Answer: Three waterborne diseases are
,◉ 2-5 mg/L.
Answer: Conventional activated sludge systems typically operate
with a DO range of:
◉ SDS.
Answer: Which of the following provides safety information for
potentially hazardous or toxic materials?
◉ alert the operator on duty.
Answer: The first step the maintenance staff should take in properly
locking and tagging out a piece of equipment is to:
◉ Denitrification.
Answer: Which of the following would NOT be considered
preliminary treatment?
◉ 19.5%.
Answer: Oxygen deficiency becomes a concern when the oxygen
level in a confined space is less than
◉ Air Lift.
,Answer: This type of pump injects compressed air into a discharge
line, which mixes and raises solids through the line due to sludge
density.
◉ Nitrification.
Answer: The appearance of duckweed in a final clarifier is an
indication of:
◉ Packing.
Answer: This material can be made from Teflon or graphite and is
used to prevent leakage between moving parts of a pump:
◉ make no adjustment.
Answer: What is the first course of action if you see a slow constant
drip from a pump shaft packing seal?
◉ mixed liquor volatile suspended solids.
Answer: Which of the following types of solids most accurately
represent the microorganisms in the activated sludge process?
◉ none, it must analyzed immediately.
Answer: What is the maximum recommended holding time for a
sample that is to be analyzed for pH?
, ◉ Reciprocating.
Answer: This type of positive displacement pump consists of a
piston that moves back and forth
◉ sodium sulfite solution.
Answer: Most DO probes come with an electronic zero for
calibration. What should be used to check the accuracy of this
feature on a DO probe?
◉ secured together.
Answer: When working in an area with two or more floor coverings
(for example, grating and checker-plate), be sure that they are
always
◉ Hydrogen sulfide.
Answer: A rotten egg smell in wastewater can most likely be
attributed to:
◉ an area where conditions are very calm and no mixing is taking
place.
Answer: A "dead" spot in an activated sludge biological reactor is
typically identified visually as
◉ bacteria.
