Water Treatment Operator Class B Licensing Exam
Questions and Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A | Instant Download Pdf
1. What is the primary purpose of coagulation in water treatment?
A. Disinfection of pathogens
B. Removal of dissolved salts
C. Destabilization of suspended particles
D. pH adjustment
Answer: C
Coagulation neutralizes charges on fine particles so they can clump
together and be removed.
2. Which chemical is most commonly used as a coagulant?
A. Sodium chloride
B. Aluminum sulfate
C. Chlorine
D. Lime
Answer: B
,Aluminum sulfate (alum) is widely used to form flocs in water
treatment.
3. The process of adding chlorine to destroy pathogens is called:
A. Flocculation
B. Sedimentation
C. Disinfection
D. Coagulation
Answer: C
Disinfection kills or inactivates disease-causing organisms.
4. What is the main purpose of sedimentation tanks?
A. Add chemicals
B. Remove settled solids
C. Increase pressure
D. Adjust pH
Answer: B
Sedimentation allows heavier particles to settle by gravity.
,5. Turbidity in water refers to:
A. Water hardness
B. Cloudiness caused by particles
C. pH level
D. Temperature
Answer: B
Turbidity measures suspended particles that reduce clarity.
6. What is the acceptable range for drinking water pH?
A. 1–3
B. 4–5
C. 6.5–8.5
D. 9–12
Answer: C
Most drinking water standards require pH between 6.5 and 8.5.
7. Which unit measures water hardness?
A. NTU
B. mg/L as CaCO₃
C. PSI
D. ppm chlorine
, Answer: B
Hardness is expressed as calcium carbonate equivalent.
8. What is flocculation?
A. Breaking particles apart
B. Slow mixing to form larger particles
C. Adding chlorine
D. Filtering water
Answer: B
Flocculation gently mixes water to form larger floc particles.
9. Which filter media is most commonly used in rapid sand filters?
A. Gravel only
B. Activated carbon only
C. Sand and anthracite
D. Clay
Answer: C
Sand and anthracite provide effective particle removal.
Questions and Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A | Instant Download Pdf
1. What is the primary purpose of coagulation in water treatment?
A. Disinfection of pathogens
B. Removal of dissolved salts
C. Destabilization of suspended particles
D. pH adjustment
Answer: C
Coagulation neutralizes charges on fine particles so they can clump
together and be removed.
2. Which chemical is most commonly used as a coagulant?
A. Sodium chloride
B. Aluminum sulfate
C. Chlorine
D. Lime
Answer: B
,Aluminum sulfate (alum) is widely used to form flocs in water
treatment.
3. The process of adding chlorine to destroy pathogens is called:
A. Flocculation
B. Sedimentation
C. Disinfection
D. Coagulation
Answer: C
Disinfection kills or inactivates disease-causing organisms.
4. What is the main purpose of sedimentation tanks?
A. Add chemicals
B. Remove settled solids
C. Increase pressure
D. Adjust pH
Answer: B
Sedimentation allows heavier particles to settle by gravity.
,5. Turbidity in water refers to:
A. Water hardness
B. Cloudiness caused by particles
C. pH level
D. Temperature
Answer: B
Turbidity measures suspended particles that reduce clarity.
6. What is the acceptable range for drinking water pH?
A. 1–3
B. 4–5
C. 6.5–8.5
D. 9–12
Answer: C
Most drinking water standards require pH between 6.5 and 8.5.
7. Which unit measures water hardness?
A. NTU
B. mg/L as CaCO₃
C. PSI
D. ppm chlorine
, Answer: B
Hardness is expressed as calcium carbonate equivalent.
8. What is flocculation?
A. Breaking particles apart
B. Slow mixing to form larger particles
C. Adding chlorine
D. Filtering water
Answer: B
Flocculation gently mixes water to form larger floc particles.
9. Which filter media is most commonly used in rapid sand filters?
A. Gravel only
B. Activated carbon only
C. Sand and anthracite
D. Clay
Answer: C
Sand and anthracite provide effective particle removal.
