AWWA WATER TREATMENT PROCESS CONTROL
CERTIFICATION EXAM QUESTIONS AND CORRECT
ANSWERS (VERIFIED ANSWERS Q&A 2026
|INSTANT DOWNLOAD PDF
1. Which process is primarily used to remove suspended solids
from raw water?
A. Chlorination
B. Coagulation and sedimentation
C. Fluoridation
D. pH adjustment
Rationale: Suspended solids are typically removed through
coagulation (to form flocs) followed by sedimentation.
Correct Answer: B. Coagulation and sedimentation
2. What is the main purpose of coagulation in water
treatment?
A. To disinfect pathogens
B. To neutralize electrical charges on particles
C. To increase water hardness
D. To remove dissolved gases
,Rationale: Coagulation destabilizes particles so they can form
larger flocs.
Correct Answer: B. To neutralize electrical charges on particles
3. Which chemical is most commonly used as a coagulant?
A. Sodium chloride
B. Aluminum sulfate
C. Calcium carbonate
D. Sodium hypochlorite
Rationale: Alum (aluminum sulfate) is widely used in water
treatment plants.
Correct Answer: B. Aluminum sulfate
4. The main purpose of flocculation is to:
A. Kill bacteria
B. Form larger particles from smaller ones
C. Adjust water pH
D. Remove dissolved salts
Rationale: Flocculation gently mixes water to form larger flocs
for settling.
Correct Answer: B. Form larger particles from smaller ones
5. Sedimentation works by using:
,A. Chemical reactions
B. Gravity
C. Electrical attraction
D. Filtration pressure
Rationale: Heavier particles settle out due to gravity.
Correct Answer: B. Gravity
6. Filtration in water treatment is mainly used to remove:
A. Dissolved salts
B. Fine suspended particles
C. Hardness ions
D. Chlorine
Rationale: Filters remove remaining fine particles after
sedimentation.
Correct Answer: B. Fine suspended particles
7. Which filter media is most commonly used?
A. Gravel only
B. Activated carbon only
C. Sand
D. Clay
Rationale: Sand is widely used in rapid and slow sand filters.
Correct Answer: C. Sand
, 8. The main purpose of disinfection is to:
A. Remove turbidity
B. Kill or inactivate pathogens
C. Remove iron
D. Improve taste
Rationale: Disinfection targets microorganisms.
Correct Answer: B. Kill or inactivate pathogens
9. Which is the most common disinfectant in water
treatment?
A. Chlorine
B. Oxygen
C. Nitrogen
D. Carbon dioxide
Rationale: Chlorine is widely used due to effectiveness and
residual protection.
Correct Answer: A. Chlorine
10. What does “turbidity” measure?
A. Water temperature
B. Cloudiness caused by particles
C. Salt content
D. Chlorine level
CERTIFICATION EXAM QUESTIONS AND CORRECT
ANSWERS (VERIFIED ANSWERS Q&A 2026
|INSTANT DOWNLOAD PDF
1. Which process is primarily used to remove suspended solids
from raw water?
A. Chlorination
B. Coagulation and sedimentation
C. Fluoridation
D. pH adjustment
Rationale: Suspended solids are typically removed through
coagulation (to form flocs) followed by sedimentation.
Correct Answer: B. Coagulation and sedimentation
2. What is the main purpose of coagulation in water
treatment?
A. To disinfect pathogens
B. To neutralize electrical charges on particles
C. To increase water hardness
D. To remove dissolved gases
,Rationale: Coagulation destabilizes particles so they can form
larger flocs.
Correct Answer: B. To neutralize electrical charges on particles
3. Which chemical is most commonly used as a coagulant?
A. Sodium chloride
B. Aluminum sulfate
C. Calcium carbonate
D. Sodium hypochlorite
Rationale: Alum (aluminum sulfate) is widely used in water
treatment plants.
Correct Answer: B. Aluminum sulfate
4. The main purpose of flocculation is to:
A. Kill bacteria
B. Form larger particles from smaller ones
C. Adjust water pH
D. Remove dissolved salts
Rationale: Flocculation gently mixes water to form larger flocs
for settling.
Correct Answer: B. Form larger particles from smaller ones
5. Sedimentation works by using:
,A. Chemical reactions
B. Gravity
C. Electrical attraction
D. Filtration pressure
Rationale: Heavier particles settle out due to gravity.
Correct Answer: B. Gravity
6. Filtration in water treatment is mainly used to remove:
A. Dissolved salts
B. Fine suspended particles
C. Hardness ions
D. Chlorine
Rationale: Filters remove remaining fine particles after
sedimentation.
Correct Answer: B. Fine suspended particles
7. Which filter media is most commonly used?
A. Gravel only
B. Activated carbon only
C. Sand
D. Clay
Rationale: Sand is widely used in rapid and slow sand filters.
Correct Answer: C. Sand
, 8. The main purpose of disinfection is to:
A. Remove turbidity
B. Kill or inactivate pathogens
C. Remove iron
D. Improve taste
Rationale: Disinfection targets microorganisms.
Correct Answer: B. Kill or inactivate pathogens
9. Which is the most common disinfectant in water
treatment?
A. Chlorine
B. Oxygen
C. Nitrogen
D. Carbon dioxide
Rationale: Chlorine is widely used due to effectiveness and
residual protection.
Correct Answer: A. Chlorine
10. What does “turbidity” measure?
A. Water temperature
B. Cloudiness caused by particles
C. Salt content
D. Chlorine level
