South Carolina Physical/Chemical
Wastewater Operator Class C Exam
Practice Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the primary purpose of coagulation in wastewater treatment?
A. To disinfect the water
B. To remove suspended solids by chemical aggregation
C. To increase pH
D. To aerate the water
Coagulation adds chemicals that cause fine particles to clump
together, making them easier to remove in subsequent
sedimentation steps.
2. What is the most commonly used coagulant in municipal wastewater
treatment?
, A. Sodium hydroxide
B. Aluminum sulfate (alum)
C. Calcium carbonate
D. Ferric chloride
Alum is widely used due to its effectiveness in destabilizing colloidal
particles.
3. The purpose of sedimentation in physical/chemical treatment is to:
A. Increase dissolved oxygen
B. Reduce nitrogen content
C. Remove suspended solids by allowing them to settle
D. Adjust pH
Sedimentation allows heavier particles to settle out under gravity.
4. What factor does NOT significantly affect coagulation efficiency?
A. Water temperature
B. pH
C. Color of water
D. Mixing intensity
While water color may indicate organic content, it does not directly
affect the chemical reactions in coagulation.
5. Flocculation is the process of:
A. Gently mixing water to promote particle aggregation after
coagulation
B. Removing bacteria
, C. Increasing water hardness
D. Adjusting pH
Flocculation encourages formation of larger flocs that can settle in
sedimentation basins.
6. What is the main purpose of filtration in wastewater treatment?
A. Remove remaining suspended solids
B. Add nutrients to the water
C. Remove dissolved oxygen
D. Lower pH
Filters physically remove particles that were not removed during
sedimentation.
7. Which type of filter is commonly used in physical/chemical
wastewater treatment?
A. Reverse osmosis
B. Activated carbon only
C. Rapid sand filter
D. Ultraviolet filter
Rapid sand filters are commonly used for polishing water after
sedimentation.
8. The term “turbidity” refers to:
A. pH
B. Temperature
C. Cloudiness caused by suspended solids
, D. Color
Turbidity is a measure of water clarity affected by particles in
suspension.
9. A typical coagulant aid used in physical/chemical treatment is:
A. Chlorine
B. Polymers (synthetic flocculants)
C. Ozone
D. Lime
Polymers enhance floc formation and improve settling.
10. What is the main chemical used for pH adjustment in
wastewater treatment?
A. Chlorine
B. Lime (Ca(OH)₂)
C. Alum
D. Fluoride
Lime raises pH and helps with chemical precipitation of metals and
phosphorus.
11. In chemical precipitation, phosphorus is typically removed using:
A. Chlorine
B. Ozone
C. Alum or ferric salts
D. Sodium hydroxide only
Wastewater Operator Class C Exam
Practice Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the primary purpose of coagulation in wastewater treatment?
A. To disinfect the water
B. To remove suspended solids by chemical aggregation
C. To increase pH
D. To aerate the water
Coagulation adds chemicals that cause fine particles to clump
together, making them easier to remove in subsequent
sedimentation steps.
2. What is the most commonly used coagulant in municipal wastewater
treatment?
, A. Sodium hydroxide
B. Aluminum sulfate (alum)
C. Calcium carbonate
D. Ferric chloride
Alum is widely used due to its effectiveness in destabilizing colloidal
particles.
3. The purpose of sedimentation in physical/chemical treatment is to:
A. Increase dissolved oxygen
B. Reduce nitrogen content
C. Remove suspended solids by allowing them to settle
D. Adjust pH
Sedimentation allows heavier particles to settle out under gravity.
4. What factor does NOT significantly affect coagulation efficiency?
A. Water temperature
B. pH
C. Color of water
D. Mixing intensity
While water color may indicate organic content, it does not directly
affect the chemical reactions in coagulation.
5. Flocculation is the process of:
A. Gently mixing water to promote particle aggregation after
coagulation
B. Removing bacteria
, C. Increasing water hardness
D. Adjusting pH
Flocculation encourages formation of larger flocs that can settle in
sedimentation basins.
6. What is the main purpose of filtration in wastewater treatment?
A. Remove remaining suspended solids
B. Add nutrients to the water
C. Remove dissolved oxygen
D. Lower pH
Filters physically remove particles that were not removed during
sedimentation.
7. Which type of filter is commonly used in physical/chemical
wastewater treatment?
A. Reverse osmosis
B. Activated carbon only
C. Rapid sand filter
D. Ultraviolet filter
Rapid sand filters are commonly used for polishing water after
sedimentation.
8. The term “turbidity” refers to:
A. pH
B. Temperature
C. Cloudiness caused by suspended solids
, D. Color
Turbidity is a measure of water clarity affected by particles in
suspension.
9. A typical coagulant aid used in physical/chemical treatment is:
A. Chlorine
B. Polymers (synthetic flocculants)
C. Ozone
D. Lime
Polymers enhance floc formation and improve settling.
10. What is the main chemical used for pH adjustment in
wastewater treatment?
A. Chlorine
B. Lime (Ca(OH)₂)
C. Alum
D. Fluoride
Lime raises pH and helps with chemical precipitation of metals and
phosphorus.
11. In chemical precipitation, phosphorus is typically removed using:
A. Chlorine
B. Ozone
C. Alum or ferric salts
D. Sodium hydroxide only
