Wastewater Treatment B Test
2026/2027 | Wastewater Operations
Study Guide | Wastewater Operator
Class B Certification Exam Preparation
Description: This comprehensive study guide contains 200 multiple-choice questions
designed to prepare candidates for the Wastewater Operator Class B Certification Exam.
Questions cover treatment processes, equipment, math, safety, regulations, and
operational troubleshooting for the 2026/2027 testing cycle.
Key Words: Wastewater Operator Class B, Certification Exam, Wastewater Treatment,
Study Guide, MCQ Practice, Activated Sludge, Disinfection, Solids Handling, Laboratory,
Safety, Regulations.
Section 1: Wastewater Characteristics and Preliminary
Treatment (Q1–Q25)
Q1. What is the primary purpose of preliminary treatment in a wastewater
treatment plant?
A) Remove dissolved solids
B) Protect downstream equipment from damage
C) Disinfect effluent
D) Stabilize sludge
Correct Answer: B ✅
Q2. A bar screen in a wastewater treatment plant is designed to remove:
A) Dissolved gases
,B) Large debris and solids
C) Pathogens
D) Nutrients
Correct Answer: B ✅
Q3. Grit typically consists of:
A) Organic matter that settles slowly
B) Heavy inorganic particles like sand and gravel
C) Floating grease
D) Dissolved salts
Correct Answer: B ✅
Q4. The purpose of a grit chamber is to:
A) Remove dissolved BOD
B) Remove heavy inorganic solids that could damage pumps
C) Aerate the wastewater
D) Disinfect the flow
Correct Answer: B ✅
Q5. What type of flow measurement device is commonly used at a treatment plant
headworks?
A) Rotameter
B) Parshall flume
C) Manometer
D) Pycnometer
Correct Answer: B ✅
Q6. Comminutors are used to:
A) Grind solids into smaller pieces
B) Remove grit
C) Add chemicals
,D) Measure flow
Correct Answer: A ✅
Q7. Which parameter measures the oxygen-consuming capacity of wastewater?
A) pH
B) BOD
C) Turbidity
D) Conductivity
Correct Answer: B ✅
Q8. BOD stands for:
A) Biological Oxygen Demand
B) Biochemical Oxygen Demand
C) Basic Oxygen Demand
D) Bacterial Oxygen Deficiency
Correct Answer: B ✅
Q9. The standard BOD test is conducted over how many days?
A) 1 day
B) 3 days
C) 5 days
D) 10 days
Correct Answer: C ✅
Q10. The BOD test is typically performed at what temperature?
A) 10°C
B) 20°C
C) 25°C
D) 37°C
Correct Answer: B ✅
Q11. TSS stands for:
A) Total Soluble Solids
, B) Total Suspended Solids
C) Total Settleable Solids
D) Total Synthetic Solids
Correct Answer: B ✅
Q12. Which of the following is a measure of the settleable solids in wastewater?
A) Imhoff cone test
B) Jar test
C) Winkler test
D) Titration
Correct Answer: A ✅
Q13. The pH scale ranges from:
A) 0 to 10
B) 1 to 12
C) 0 to 14
D) 1 to 14
Correct Answer: C ✅
Q14. Normal raw domestic wastewater pH is typically:
A) 2–4
B) 6.5–8.0
C) 9–11
D) 12–14
Correct Answer: B ✅
Q15. FOG in wastewater stands for:
A) Fats, Oils, and Grease
B) Floating Organic Grit
C) Fine Organic Granules
D) Fresh Organic Waste
Correct Answer: A ✅
2026/2027 | Wastewater Operations
Study Guide | Wastewater Operator
Class B Certification Exam Preparation
Description: This comprehensive study guide contains 200 multiple-choice questions
designed to prepare candidates for the Wastewater Operator Class B Certification Exam.
Questions cover treatment processes, equipment, math, safety, regulations, and
operational troubleshooting for the 2026/2027 testing cycle.
Key Words: Wastewater Operator Class B, Certification Exam, Wastewater Treatment,
Study Guide, MCQ Practice, Activated Sludge, Disinfection, Solids Handling, Laboratory,
Safety, Regulations.
Section 1: Wastewater Characteristics and Preliminary
Treatment (Q1–Q25)
Q1. What is the primary purpose of preliminary treatment in a wastewater
treatment plant?
A) Remove dissolved solids
B) Protect downstream equipment from damage
C) Disinfect effluent
D) Stabilize sludge
Correct Answer: B ✅
Q2. A bar screen in a wastewater treatment plant is designed to remove:
A) Dissolved gases
,B) Large debris and solids
C) Pathogens
D) Nutrients
Correct Answer: B ✅
Q3. Grit typically consists of:
A) Organic matter that settles slowly
B) Heavy inorganic particles like sand and gravel
C) Floating grease
D) Dissolved salts
Correct Answer: B ✅
Q4. The purpose of a grit chamber is to:
A) Remove dissolved BOD
B) Remove heavy inorganic solids that could damage pumps
C) Aerate the wastewater
D) Disinfect the flow
Correct Answer: B ✅
Q5. What type of flow measurement device is commonly used at a treatment plant
headworks?
A) Rotameter
B) Parshall flume
C) Manometer
D) Pycnometer
Correct Answer: B ✅
Q6. Comminutors are used to:
A) Grind solids into smaller pieces
B) Remove grit
C) Add chemicals
,D) Measure flow
Correct Answer: A ✅
Q7. Which parameter measures the oxygen-consuming capacity of wastewater?
A) pH
B) BOD
C) Turbidity
D) Conductivity
Correct Answer: B ✅
Q8. BOD stands for:
A) Biological Oxygen Demand
B) Biochemical Oxygen Demand
C) Basic Oxygen Demand
D) Bacterial Oxygen Deficiency
Correct Answer: B ✅
Q9. The standard BOD test is conducted over how many days?
A) 1 day
B) 3 days
C) 5 days
D) 10 days
Correct Answer: C ✅
Q10. The BOD test is typically performed at what temperature?
A) 10°C
B) 20°C
C) 25°C
D) 37°C
Correct Answer: B ✅
Q11. TSS stands for:
A) Total Soluble Solids
, B) Total Suspended Solids
C) Total Settleable Solids
D) Total Synthetic Solids
Correct Answer: B ✅
Q12. Which of the following is a measure of the settleable solids in wastewater?
A) Imhoff cone test
B) Jar test
C) Winkler test
D) Titration
Correct Answer: A ✅
Q13. The pH scale ranges from:
A) 0 to 10
B) 1 to 12
C) 0 to 14
D) 1 to 14
Correct Answer: C ✅
Q14. Normal raw domestic wastewater pH is typically:
A) 2–4
B) 6.5–8.0
C) 9–11
D) 12–14
Correct Answer: B ✅
Q15. FOG in wastewater stands for:
A) Fats, Oils, and Grease
B) Floating Organic Grit
C) Fine Organic Granules
D) Fresh Organic Waste
Correct Answer: A ✅
