Page 1 of 105
South Carolina Physical/Chemical Wastewater Operator Class
C Exam COMPLETE QUESTIONS AND DETAILED SOLUTIONS
LATEST UPDATE THIS YEAR-JUST RELEASED
SUMMARIZED EXAM COVERAGE
The Class C Physical/Chemical Wastewater Operator exam focuses on fundamental treatment processes,
including screening, sedimentation, chemical dosing, and disinfection. It also tests operator safety, basic
laboratory procedures, equipment operation, and compliance with environmental regulations. Emphasis
is placed on practical plant operation and troubleshooting.
1.
A wastewater operator notices high turbidity in effluent leaving the primary clarifier. What is the most
likely cause?
A. Excessive chlorination
B. Poor sedimentation or hydraulic overload in clarifier
C. Low pump speed
D. High dissolved oxygen
Answer: B
Rationale: Poor settling or overload reduces solids removal efficiency.
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2.
A plant operator observes a strong hydrogen sulfide odor in the headworks area. What is the primary
concern?
A. Improved treatment efficiency
B. Toxic gas exposure hazard
C. Increased oxygen levels
D. Better disinfection
Answer: B
Rationale: Hydrogen sulfide is toxic and dangerous at high levels.
3.
A screen at the influent channel is clogging frequently. What is the best operational response?
A. Remove screening device
B. Increase maintenance frequency and cleaning
C. Reduce flow permanently
D. Stop treatment process
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Answer: B
Rationale: Regular cleaning prevents clogging and system overload.
4.
A chemical feed system is overdosing alum in the treatment process. What is the likely effect?
A. Increased pH stability
B. Excess sludge production and pH reduction
C. Improved disinfection only
D. Reduced solids formation
Answer: B
Rationale: Overdosing coagulants increases sludge and lowers pH.
5.
An operator measures low chlorine residual in the effluent. What is the most likely issue?
A. Excess chlorination
B. Insufficient chlorine dose or high demand
C. High pH only
D. Low temperature only
, Page 4 of 105
Answer: B
Rationale: Low residual indicates inadequate disinfection.
6.
A grit chamber is not removing sand effectively. What is the probable cause?
A. Excess flow velocity
B. Correct hydraulic retention time
C. Too much oxygen
D. Low sludge production
Answer: A
Rationale: High velocity prevents grit settling.
7.
A wastewater operator notices excessive foam in aeration basins. What is a likely cause?
A. Proper aeration
B. Surfactants or biological imbalance
C. Low flow
D. High sedimentation
South Carolina Physical/Chemical Wastewater Operator Class
C Exam COMPLETE QUESTIONS AND DETAILED SOLUTIONS
LATEST UPDATE THIS YEAR-JUST RELEASED
SUMMARIZED EXAM COVERAGE
The Class C Physical/Chemical Wastewater Operator exam focuses on fundamental treatment processes,
including screening, sedimentation, chemical dosing, and disinfection. It also tests operator safety, basic
laboratory procedures, equipment operation, and compliance with environmental regulations. Emphasis
is placed on practical plant operation and troubleshooting.
1.
A wastewater operator notices high turbidity in effluent leaving the primary clarifier. What is the most
likely cause?
A. Excessive chlorination
B. Poor sedimentation or hydraulic overload in clarifier
C. Low pump speed
D. High dissolved oxygen
Answer: B
Rationale: Poor settling or overload reduces solids removal efficiency.
, Page 2 of 105
2.
A plant operator observes a strong hydrogen sulfide odor in the headworks area. What is the primary
concern?
A. Improved treatment efficiency
B. Toxic gas exposure hazard
C. Increased oxygen levels
D. Better disinfection
Answer: B
Rationale: Hydrogen sulfide is toxic and dangerous at high levels.
3.
A screen at the influent channel is clogging frequently. What is the best operational response?
A. Remove screening device
B. Increase maintenance frequency and cleaning
C. Reduce flow permanently
D. Stop treatment process
, Page 3 of 105
Answer: B
Rationale: Regular cleaning prevents clogging and system overload.
4.
A chemical feed system is overdosing alum in the treatment process. What is the likely effect?
A. Increased pH stability
B. Excess sludge production and pH reduction
C. Improved disinfection only
D. Reduced solids formation
Answer: B
Rationale: Overdosing coagulants increases sludge and lowers pH.
5.
An operator measures low chlorine residual in the effluent. What is the most likely issue?
A. Excess chlorination
B. Insufficient chlorine dose or high demand
C. High pH only
D. Low temperature only
, Page 4 of 105
Answer: B
Rationale: Low residual indicates inadequate disinfection.
6.
A grit chamber is not removing sand effectively. What is the probable cause?
A. Excess flow velocity
B. Correct hydraulic retention time
C. Too much oxygen
D. Low sludge production
Answer: A
Rationale: High velocity prevents grit settling.
7.
A wastewater operator notices excessive foam in aeration basins. What is a likely cause?
A. Proper aeration
B. Surfactants or biological imbalance
C. Low flow
D. High sedimentation
