AK Wastewater Treatment Contractor
Exam — Practice Exam Practice
Questions And Correct Answers
(Verified Answers) Plus Rationales 2027
Q&A | Instant Download Pdf
Q1. What is the primary purpose of a wastewater treatment system?
A. Increase wastewater temperature
B. Store wastewater indefinitely
C. Remove pollutants and protect public health and the environment
D. Increase wastewater flow
Answer: C. Remove pollutants and protect public health and the
environment
Rationale: Wastewater treatment is intended to reduce contaminants and
pathogens before treated effluent is discharged or otherwise managed.
,Q2. Which treatment stage normally removes large debris such as rags,
sticks, and plastics?
A. Disinfection
B. Screening
C. Aeration
D. Sludge digestion
Answer: B. Screening
Rationale: Screens are installed early in the treatment process to remove
large materials that could damage pumps and downstream equipment.
Q3. What is the primary purpose of grit removal?
A. Remove dissolved oxygen
B. Remove fine microorganisms
C. Remove sand, gravel, and other dense inorganic particles
D. Increase BOD
Answer: C. Remove sand, gravel, and other dense inorganic particles
Rationale: Grit can cause abrasion, accumulation, and reduced capacity in
pumps, channels, tanks, and sludge-handling equipment.
,Q4. Which parameter measures the amount of oxygen microorganisms
require to biologically oxidize biodegradable organic matter?
A. TSS
B. BOD
C. pH
D. DO
Answer: B. BOD
Rationale: Biochemical oxygen demand, or BOD, indicates the oxygen
demand associated with biodegradable organic material in wastewater.
Q5. What does TSS stand for?
A. Total Soluble Salts
B. Total Suspended Solids
C. Treated Sewer Solids
D. Total Settling System
Answer: B. Total Suspended Solids
Rationale: TSS represents suspended particulate matter that can be
retained by the applicable laboratory filtration procedure.
, Q6. What is the primary purpose of a primary clarifier?
A. Disinfect effluent
B. Remove settleable solids and floatable material
C. Add oxygen to activated sludge
D. Neutralize chlorine
Answer: B. Remove settleable solids and floatable material
Rationale: Primary clarification relies mainly on gravity separation to
remove settleable solids and floating materials before biological
treatment.
Q7. Which process is commonly used for secondary biological treatment?
A. Activated sludge
B. Bar screening
C. Grit washing
D. Chlorine storage
Answer: A. Activated sludge
Rationale: Activated sludge uses microorganisms to biologically consume
and transform organic pollutants in wastewater.
Exam — Practice Exam Practice
Questions And Correct Answers
(Verified Answers) Plus Rationales 2027
Q&A | Instant Download Pdf
Q1. What is the primary purpose of a wastewater treatment system?
A. Increase wastewater temperature
B. Store wastewater indefinitely
C. Remove pollutants and protect public health and the environment
D. Increase wastewater flow
Answer: C. Remove pollutants and protect public health and the
environment
Rationale: Wastewater treatment is intended to reduce contaminants and
pathogens before treated effluent is discharged or otherwise managed.
,Q2. Which treatment stage normally removes large debris such as rags,
sticks, and plastics?
A. Disinfection
B. Screening
C. Aeration
D. Sludge digestion
Answer: B. Screening
Rationale: Screens are installed early in the treatment process to remove
large materials that could damage pumps and downstream equipment.
Q3. What is the primary purpose of grit removal?
A. Remove dissolved oxygen
B. Remove fine microorganisms
C. Remove sand, gravel, and other dense inorganic particles
D. Increase BOD
Answer: C. Remove sand, gravel, and other dense inorganic particles
Rationale: Grit can cause abrasion, accumulation, and reduced capacity in
pumps, channels, tanks, and sludge-handling equipment.
,Q4. Which parameter measures the amount of oxygen microorganisms
require to biologically oxidize biodegradable organic matter?
A. TSS
B. BOD
C. pH
D. DO
Answer: B. BOD
Rationale: Biochemical oxygen demand, or BOD, indicates the oxygen
demand associated with biodegradable organic material in wastewater.
Q5. What does TSS stand for?
A. Total Soluble Salts
B. Total Suspended Solids
C. Treated Sewer Solids
D. Total Settling System
Answer: B. Total Suspended Solids
Rationale: TSS represents suspended particulate matter that can be
retained by the applicable laboratory filtration procedure.
, Q6. What is the primary purpose of a primary clarifier?
A. Disinfect effluent
B. Remove settleable solids and floatable material
C. Add oxygen to activated sludge
D. Neutralize chlorine
Answer: B. Remove settleable solids and floatable material
Rationale: Primary clarification relies mainly on gravity separation to
remove settleable solids and floating materials before biological
treatment.
Q7. Which process is commonly used for secondary biological treatment?
A. Activated sludge
B. Bar screening
C. Grit washing
D. Chlorine storage
Answer: A. Activated sludge
Rationale: Activated sludge uses microorganisms to biologically consume
and transform organic pollutants in wastewater.
