WASTEWATER TREATMENT OPERATOR {test 2&3}
CERTIFICATION EXAM 2025-2026 ACTUAL EXAM 160
QUESTIONS AND CORRECT DETAILED ANSWERS
|ALREADY GRADED A+
Overview
Developed to reflect the structure and rigor of the Wastewater Treatment Operator Certification
Exam (Tests 2 & 3), this comprehensive study resource reinforces critical concepts in wastewater
management, treatment processes, safety procedures, environmental regulations, and operational
best practices. Aligned with the 2025–2026 curriculum, it equips students with the knowledge
and confidence to excel on the exam and achieve top performance.
─────────────────────────────
Key Features
✅ 160 Verified Questions with Detailed Correct Answers
✅ Updated for Wastewater Treatment Operator Certification 2025–2026 Curriculum
✅ Real Exam-Style Format for Accurate Preparation
✅ Covers Core Topics: Treatment Processes, Water Quality, Safety Protocols, Regulatory
Compliance, and Plant Operations
✅ A+ Graded Content for Accuracy and Reliability
─────────────────────────────
Purpose
• To provide a complete, high-quality review for the Wastewater Treatment Operator
Certification Exam
• To strengthen understanding of treatment operations, safety, and regulatory compliance
• To help students achieve top exam scores and operational competency
─────────────────────────────
Recommended For
• Students preparing for the Wastewater Treatment Operator Certification Exam (Tests 2 & 3)
• Learners seeking to enhance knowledge in wastewater management and plant operations
• Educators and trainers developing high-quality study support materials
─────────────────────────────
Your Complete Wastewater Treatment Operator Study Resource
With 160 verified questions and detailed correct answers, the Wastewater Treatment Operator
Certification Exam 2025–2026 Test Bank (Tests 2 & 3) is your most reliable, up-to-date, and
effective tool for mastering wastewater treatment principles and passing your exam with
confidence.
, Test2
What is the typical BOD removal efficiency in a primary clarifier?
A) 10 to 15%
B) 40 to 60%
C) 20 to 50%
D) 95 to 99% - ANSWER-C) 20 to 50% (v.1 pg 129)
What does the "F" in F/M ratio represent?
A) The microorganism population in the aeration tank
B) The amount of filamentous bacteria in the activated sludge process
C) The MLVSS in the aeration tank
D) The food for the microorganisms flowing into the aeration tank, in lbs/day - ANSWER-D) The food for
the microorganisms flowing into the aeration tank, in lbs/day (v.2 pg 58)
Which of the following describes the appearance of healthy activated sludge?
A) Thick, greasy, dark tan foam
B) Brown with a moderate amount of crisp, white foam
C) Clear liquid with clear foam
D) Gray liquid with no foam - ANSWER-B) Brown with a moderate amount of crisp, white foam
What is used to control filamentous organisms?
A) Polymer
B) Sulfur Dioxide
C) Coagulant
D) Chlorine - ANSWER-D) Chlorine (v.1 pg 399)
What are commonly used to control chlorine feed rate for disinfection?
,A) BOD and MLVSS
B) pH and temperature
C) Flow and chlorine residual
D) DO and TSS - ANSWER-C) Flow and chlorine residual (v.1 pg 356)
Which toxic gas is commonly found in septic wastewater and smells like rotten eggs?
A) Hydrogen Sulfide
B) Carbon monoxide
C) Hydrogen
D) Carbon Dioxide - ANSWER-A) Hydrogen Sulfide (v.2 pg 299)
What is the permissible exposure limit for chlorine gas vapor during a normal 8 hour workday and a 40
hour work week?
A) 0.1 ppm
B) 0.5 ppm
C) 1 ppm
D) 15 ppm - ANSWER-B) 0.5 ppm (v.2 pg 268)
What is a vulnerability assessment?
A) Assesses the impact of hydrogen sulfide to a concrete structure
B) Analyzes the impact of flow and infiltration problem to the plant hydraulics
C) Estimates the vulnerability of aquatic wildlife to excessive algae growth
D) Contingency planning to determine the vulnerability of the utility during various types of emergencies
and identify corrective actions to reduce the risks - ANSWER-D) Contingency planning to determine
the vulnerability of the utility during various types of emergencies and identify corrective actions to
reduce the risks (v.2 pg 722)
, What is the difference between the settling rate of activated sludge and raw sludge?
A) Activated sludge settles slightly faster than raw sludge
B) Activated sludge settles at the same rate as raw sludge
C) Activated sludge settles slower than raw sludge
D) Activated sludge settles much faster than raw sludge - ANSWER-C) Activated sludge settles slower
than raw sludge (v.1 pg 109)
What should be mostly found in healthy activated sludge?
A) Tiny flagellates
B) Amoeboids
C) Short Filaments
D) Free swimmers and stalked ciliates - ANSWER-D) Free swimmers and stalked ciliates (v.2 pg 120,124)
One to two percent of the digester gas in an anaerobic consists of
A) Hydrogen, Nitrogen, Hydrogen sulfide, and other gases
B) Methane
C) Carbon Dioxide
D) CH_4 - ANSWER-A) Hydrogen, Nitrogen, Hydrogen sulfide, and other gases (v.2 pg 158)
What is true during the colder winter months?
A) Modify operations to decrease solids under aeration to provide less microorganisms to treat the BOD
B) Modify operations to increase solids under aeration to provide more microorganisms to treat the BOD
C) Biological activity will increase, which results in more overall sludge production
D) Microorganisms become more active - ANSWER-B) Modify operations to increase solids under
aeration to provide more microorganisms to treat the BOD (v.2 pg 71)
What type of sludge would you expect in an aeration tank if the content is dark and has low DO?
CERTIFICATION EXAM 2025-2026 ACTUAL EXAM 160
QUESTIONS AND CORRECT DETAILED ANSWERS
|ALREADY GRADED A+
Overview
Developed to reflect the structure and rigor of the Wastewater Treatment Operator Certification
Exam (Tests 2 & 3), this comprehensive study resource reinforces critical concepts in wastewater
management, treatment processes, safety procedures, environmental regulations, and operational
best practices. Aligned with the 2025–2026 curriculum, it equips students with the knowledge
and confidence to excel on the exam and achieve top performance.
─────────────────────────────
Key Features
✅ 160 Verified Questions with Detailed Correct Answers
✅ Updated for Wastewater Treatment Operator Certification 2025–2026 Curriculum
✅ Real Exam-Style Format for Accurate Preparation
✅ Covers Core Topics: Treatment Processes, Water Quality, Safety Protocols, Regulatory
Compliance, and Plant Operations
✅ A+ Graded Content for Accuracy and Reliability
─────────────────────────────
Purpose
• To provide a complete, high-quality review for the Wastewater Treatment Operator
Certification Exam
• To strengthen understanding of treatment operations, safety, and regulatory compliance
• To help students achieve top exam scores and operational competency
─────────────────────────────
Recommended For
• Students preparing for the Wastewater Treatment Operator Certification Exam (Tests 2 & 3)
• Learners seeking to enhance knowledge in wastewater management and plant operations
• Educators and trainers developing high-quality study support materials
─────────────────────────────
Your Complete Wastewater Treatment Operator Study Resource
With 160 verified questions and detailed correct answers, the Wastewater Treatment Operator
Certification Exam 2025–2026 Test Bank (Tests 2 & 3) is your most reliable, up-to-date, and
effective tool for mastering wastewater treatment principles and passing your exam with
confidence.
, Test2
What is the typical BOD removal efficiency in a primary clarifier?
A) 10 to 15%
B) 40 to 60%
C) 20 to 50%
D) 95 to 99% - ANSWER-C) 20 to 50% (v.1 pg 129)
What does the "F" in F/M ratio represent?
A) The microorganism population in the aeration tank
B) The amount of filamentous bacteria in the activated sludge process
C) The MLVSS in the aeration tank
D) The food for the microorganisms flowing into the aeration tank, in lbs/day - ANSWER-D) The food for
the microorganisms flowing into the aeration tank, in lbs/day (v.2 pg 58)
Which of the following describes the appearance of healthy activated sludge?
A) Thick, greasy, dark tan foam
B) Brown with a moderate amount of crisp, white foam
C) Clear liquid with clear foam
D) Gray liquid with no foam - ANSWER-B) Brown with a moderate amount of crisp, white foam
What is used to control filamentous organisms?
A) Polymer
B) Sulfur Dioxide
C) Coagulant
D) Chlorine - ANSWER-D) Chlorine (v.1 pg 399)
What are commonly used to control chlorine feed rate for disinfection?
,A) BOD and MLVSS
B) pH and temperature
C) Flow and chlorine residual
D) DO and TSS - ANSWER-C) Flow and chlorine residual (v.1 pg 356)
Which toxic gas is commonly found in septic wastewater and smells like rotten eggs?
A) Hydrogen Sulfide
B) Carbon monoxide
C) Hydrogen
D) Carbon Dioxide - ANSWER-A) Hydrogen Sulfide (v.2 pg 299)
What is the permissible exposure limit for chlorine gas vapor during a normal 8 hour workday and a 40
hour work week?
A) 0.1 ppm
B) 0.5 ppm
C) 1 ppm
D) 15 ppm - ANSWER-B) 0.5 ppm (v.2 pg 268)
What is a vulnerability assessment?
A) Assesses the impact of hydrogen sulfide to a concrete structure
B) Analyzes the impact of flow and infiltration problem to the plant hydraulics
C) Estimates the vulnerability of aquatic wildlife to excessive algae growth
D) Contingency planning to determine the vulnerability of the utility during various types of emergencies
and identify corrective actions to reduce the risks - ANSWER-D) Contingency planning to determine
the vulnerability of the utility during various types of emergencies and identify corrective actions to
reduce the risks (v.2 pg 722)
, What is the difference between the settling rate of activated sludge and raw sludge?
A) Activated sludge settles slightly faster than raw sludge
B) Activated sludge settles at the same rate as raw sludge
C) Activated sludge settles slower than raw sludge
D) Activated sludge settles much faster than raw sludge - ANSWER-C) Activated sludge settles slower
than raw sludge (v.1 pg 109)
What should be mostly found in healthy activated sludge?
A) Tiny flagellates
B) Amoeboids
C) Short Filaments
D) Free swimmers and stalked ciliates - ANSWER-D) Free swimmers and stalked ciliates (v.2 pg 120,124)
One to two percent of the digester gas in an anaerobic consists of
A) Hydrogen, Nitrogen, Hydrogen sulfide, and other gases
B) Methane
C) Carbon Dioxide
D) CH_4 - ANSWER-A) Hydrogen, Nitrogen, Hydrogen sulfide, and other gases (v.2 pg 158)
What is true during the colder winter months?
A) Modify operations to decrease solids under aeration to provide less microorganisms to treat the BOD
B) Modify operations to increase solids under aeration to provide more microorganisms to treat the BOD
C) Biological activity will increase, which results in more overall sludge production
D) Microorganisms become more active - ANSWER-B) Modify operations to increase solids under
aeration to provide more microorganisms to treat the BOD (v.2 pg 71)
What type of sludge would you expect in an aeration tank if the content is dark and has low DO?
