WasteWater Operator class C exam practice
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A colored dye solution is added into the raw wastewater entering a primary settling tank.
The dye color was noticeable in the effluent in 15 min and all of the color had passed
through the tank in 40 min. What does this indicate?
A. Wastewater is passing through the tank too fast for effective settling
B. Optimal detention time is being achieved
C. This tank has a detention time of 40 min.
D. This tank design has a detention time of 55 min. - CORRECT ANSWER: A.
Wastewater is passing through the tank too fast for effective settling
A decrease in temperature will have what effect on disinfection?
A. Require longer contact time
B. Require shorter contact time
C. Increase rate of disinfection
D. Have no effect on disinfection - CORRECT ANSWER: A. Require longer contact time
A good settling sludge would consist of what type of protozoa?
A. Rotifers and nematodes
B. Amoebas and Flagellates
C. Stalked ciliates and mastagoria
,D. Free swimmers and stalk ciliates - CORRECT ANSWER: D. Free swimmers and
stalk ciliates
A plant with a flow of 1 MGD should be monitored
A. Continuously
B. Intermittently
C. Daily
D. Every four hours depending on surface load - CORRECT ANSWER: A. Continuously
According to FAC Ch. 62-600, Domestic WasteWater Facilities, your job s an operator
during major process breakdowns is to?
A. Maintain competent documentation and record keeping
B. Report to the DEP within 24 hours after the problem is fixed
C. Call the fire department
D. Shut down the plant immediately - CORRECT ANSWER: A. Maintain competent
documentation and record keeping
After removing the roof of the chlorinator storage, building during the summer, the Cl2
stop feeding, what is the cause?
A. The CPRV became clogged
B. The tank got hotter than the manifold
C. The external pressure reducer failed
D. The tank is empty - CORRECT ANSWER: B. The tank got hotter than the manifold
Amperometric titration is used to measure
, A. Dissolved solids
B. Chlorine residual
C. Colloids
D. Emulsions - CORRECT ANSWER: B. Chlorine residual
As an operator, how do you control the anaerobic digestion process?
A. Microbial population and temperature
B. H2S and methane concentration
C. Temperature and rate of raw sludge feed
D. Methane and Co2 production - CORRECT ANSWER: C. Temperature and rate of raw
sludge feed
At what pH would disinfection be at its greatest?
A. 9
B. 7
C. 6.5
D. 5 - CORRECT ANSWER: D. 5
Before operating any piece of equipment what should be done?
A. Lock out Tag out (remember, safety first!)
B. Read O & M manual
C. Read manufacturers manual
D. Notify supervisor - CORRECT ANSWER: C. Read manufacturers manual
review Latest Update 2025-2026 100 Questions
and 100% Verified Correct Answers Guaranteed
A+
A colored dye solution is added into the raw wastewater entering a primary settling tank.
The dye color was noticeable in the effluent in 15 min and all of the color had passed
through the tank in 40 min. What does this indicate?
A. Wastewater is passing through the tank too fast for effective settling
B. Optimal detention time is being achieved
C. This tank has a detention time of 40 min.
D. This tank design has a detention time of 55 min. - CORRECT ANSWER: A.
Wastewater is passing through the tank too fast for effective settling
A decrease in temperature will have what effect on disinfection?
A. Require longer contact time
B. Require shorter contact time
C. Increase rate of disinfection
D. Have no effect on disinfection - CORRECT ANSWER: A. Require longer contact time
A good settling sludge would consist of what type of protozoa?
A. Rotifers and nematodes
B. Amoebas and Flagellates
C. Stalked ciliates and mastagoria
,D. Free swimmers and stalk ciliates - CORRECT ANSWER: D. Free swimmers and
stalk ciliates
A plant with a flow of 1 MGD should be monitored
A. Continuously
B. Intermittently
C. Daily
D. Every four hours depending on surface load - CORRECT ANSWER: A. Continuously
According to FAC Ch. 62-600, Domestic WasteWater Facilities, your job s an operator
during major process breakdowns is to?
A. Maintain competent documentation and record keeping
B. Report to the DEP within 24 hours after the problem is fixed
C. Call the fire department
D. Shut down the plant immediately - CORRECT ANSWER: A. Maintain competent
documentation and record keeping
After removing the roof of the chlorinator storage, building during the summer, the Cl2
stop feeding, what is the cause?
A. The CPRV became clogged
B. The tank got hotter than the manifold
C. The external pressure reducer failed
D. The tank is empty - CORRECT ANSWER: B. The tank got hotter than the manifold
Amperometric titration is used to measure
, A. Dissolved solids
B. Chlorine residual
C. Colloids
D. Emulsions - CORRECT ANSWER: B. Chlorine residual
As an operator, how do you control the anaerobic digestion process?
A. Microbial population and temperature
B. H2S and methane concentration
C. Temperature and rate of raw sludge feed
D. Methane and Co2 production - CORRECT ANSWER: C. Temperature and rate of raw
sludge feed
At what pH would disinfection be at its greatest?
A. 9
B. 7
C. 6.5
D. 5 - CORRECT ANSWER: D. 5
Before operating any piece of equipment what should be done?
A. Lock out Tag out (remember, safety first!)
B. Read O & M manual
C. Read manufacturers manual
D. Notify supervisor - CORRECT ANSWER: C. Read manufacturers manual
