AWWA RESIDUALS MANAGEMENT OPERATOR
CERTIFICATION EXAM QUESTIONS AND CORRECT
ANSWERS (VERIFIED ANSWERS) Q&A 2026
|INSTANT DOWNLOAD PDF
1. What are “residuals” in a water treatment plant?
A. Treated drinking water
B. Chemicals added for disinfection
C. Solid and liquid wastes generated during treatment
D. Raw source water
Rationale: Residuals are by-products such as sludge, backwash
water, and settled solids from treatment processes.
Correct Answer: C
2. Which process produces the largest volume of residuals in
conventional water treatment?
A. Chlorination
B. Coagulation and sedimentation
C. Fluoridation
D. Aeration
Rationale: Coagulation and sedimentation generate sludge
from removed suspended solids.
Correct Answer: B
,3. What is the primary purpose of sludge thickening?
A. Increase water turbidity
B. Reduce volume of sludge
C. Increase chlorine demand
D. Convert sludge into gas
Rationale: Thickening removes excess water to reduce sludge
handling volume.
Correct Answer: B
4. Which of the following is a common sludge dewatering
method?
A. Filtration through sand only
B. Centrifugation
C. UV irradiation
D. Chlorination
Rationale: Centrifuges separate solids from liquids in sludge.
Correct Answer: B
5. What is the main purpose of residuals management in
water treatment?
A. Increase chemical usage
B. Protect public health and the environment
,C. Increase water hardness
D. Improve taste of water
Rationale: Proper residuals management prevents pollution
and ensures regulatory compliance.
Correct Answer: B
6. Which chemical is commonly used to condition sludge
before dewatering?
A. Sodium chloride
B. Polymer
C. Oxygen
D. Fluoride
Rationale: Polymers help bind particles to improve dewatering
efficiency.
Correct Answer: B
7. What is “backwash water”?
A. Raw untreated water
B. Water used to clean filters
C. Finished drinking water
D. Chemical feed water
Rationale: Backwash water is used to clean filter media and
contains trapped solids.
Correct Answer: B
, 8. What is the most common disposal method for treated
sludge in many systems?
A. Ocean dumping
B. Land application
C. Freezing
D. Evaporation only
Rationale: Land application is widely used when sludge meets
safety standards.
Correct Answer: B
9. What does sludge “conditioning” involve?
A. Heating water above boiling
B. Adding chemicals to improve dewatering
C. Removing chlorine
D. Increasing oxygen levels
Rationale: Conditioning improves sludge structure for easier
water removal.
Correct Answer: B
10. Which parameter is most important when monitoring
sludge thickening performance?
A. pH only
B. Solids concentration
CERTIFICATION EXAM QUESTIONS AND CORRECT
ANSWERS (VERIFIED ANSWERS) Q&A 2026
|INSTANT DOWNLOAD PDF
1. What are “residuals” in a water treatment plant?
A. Treated drinking water
B. Chemicals added for disinfection
C. Solid and liquid wastes generated during treatment
D. Raw source water
Rationale: Residuals are by-products such as sludge, backwash
water, and settled solids from treatment processes.
Correct Answer: C
2. Which process produces the largest volume of residuals in
conventional water treatment?
A. Chlorination
B. Coagulation and sedimentation
C. Fluoridation
D. Aeration
Rationale: Coagulation and sedimentation generate sludge
from removed suspended solids.
Correct Answer: B
,3. What is the primary purpose of sludge thickening?
A. Increase water turbidity
B. Reduce volume of sludge
C. Increase chlorine demand
D. Convert sludge into gas
Rationale: Thickening removes excess water to reduce sludge
handling volume.
Correct Answer: B
4. Which of the following is a common sludge dewatering
method?
A. Filtration through sand only
B. Centrifugation
C. UV irradiation
D. Chlorination
Rationale: Centrifuges separate solids from liquids in sludge.
Correct Answer: B
5. What is the main purpose of residuals management in
water treatment?
A. Increase chemical usage
B. Protect public health and the environment
,C. Increase water hardness
D. Improve taste of water
Rationale: Proper residuals management prevents pollution
and ensures regulatory compliance.
Correct Answer: B
6. Which chemical is commonly used to condition sludge
before dewatering?
A. Sodium chloride
B. Polymer
C. Oxygen
D. Fluoride
Rationale: Polymers help bind particles to improve dewatering
efficiency.
Correct Answer: B
7. What is “backwash water”?
A. Raw untreated water
B. Water used to clean filters
C. Finished drinking water
D. Chemical feed water
Rationale: Backwash water is used to clean filter media and
contains trapped solids.
Correct Answer: B
, 8. What is the most common disposal method for treated
sludge in many systems?
A. Ocean dumping
B. Land application
C. Freezing
D. Evaporation only
Rationale: Land application is widely used when sludge meets
safety standards.
Correct Answer: B
9. What does sludge “conditioning” involve?
A. Heating water above boiling
B. Adding chemicals to improve dewatering
C. Removing chlorine
D. Increasing oxygen levels
Rationale: Conditioning improves sludge structure for easier
water removal.
Correct Answer: B
10. Which parameter is most important when monitoring
sludge thickening performance?
A. pH only
B. Solids concentration
