Oklahoma Wastewater Operator Class
D Exam Practice Questions And
Correct Answers (Verified Answers)
Plus Rationale 2027 Q&A| Instant
Download Pdf.
1. Which statement best describes the primary purpose of a
wastewater treatment facility?
A. To produce potable drinking water
B. To increase the hydraulic capacity of a sewer system
C. To remove or reduce pollutants so wastewater can be discharged
safely and protect public health and the environment
D. To eliminate the need for wastewater collection systems
The fundamental purpose of wastewater treatment is to reduce
physical, chemical, and biological pollutants before treated wastewater
is discharged or otherwise managed.
2. Which wastewater characteristic refers specifically to the amount
of oxygen microorganisms require to biologically decompose
biodegradable organic matter?
,A. Total dissolved solids
B. Biochemical oxygen demand (BOD)
C. Alkalinity
D. Turbidity
BOD indicates the amount of dissolved oxygen consumed by
microorganisms while stabilizing biodegradable organic material in
wastewater.
3. What is the principal function of a wastewater collection system?
A. Disinfect treated effluent
B. Remove dissolved nutrients
C. Transport wastewater from its source to a treatment facility
D. Digest wastewater sludge
Collection systems convey domestic, commercial, and other permitted
wastewater flows to treatment facilities for processing.
4. Which device is commonly used during preliminary wastewater
treatment to remove large floating and suspended debris?
A. Trickling filter
B. Secondary clarifier
C. Bar screen
D. Chlorine contact basin
Bar screens intercept large objects such as rags, sticks, plastics, and
other debris that could damage downstream equipment.
, 5. What is the primary purpose of grit removal?
A. Remove dissolved ammonia
B. Increase dissolved oxygen
C. Remove heavy inorganic particles such as sand, gravel, and grit
D. Destroy pathogenic organisms
Grit removal protects pumps and other equipment by removing dense
inorganic solids that can cause abrasion, clogging, and excessive
accumulation.
6. What is the main purpose of primary sedimentation?
A. Oxidize ammonia biologically
B. Remove settleable solids and some floating material by gravity
C. Disinfect wastewater
D. Increase wastewater temperature
Primary sedimentation allows heavier solids to settle and lighter
materials to float, reducing the solids and organic load entering
subsequent treatment processes.
7. Which treatment stage primarily uses microorganisms to remove
biodegradable organic matter from wastewater?
A. Screening
B. Grit removal
C. Secondary treatment
D. Preliminary treatment
, Secondary treatment relies primarily on biological processes in which
microorganisms consume and transform biodegradable organic
pollutants.
8. What is the primary function of an aeration basin in an activated-
sludge process?
A. Remove grit by gravity
B. Store disinfected effluent
C. Provide oxygen and mixing so microorganisms can biologically treat
wastewater
D. Concentrate screenings
Aeration supplies oxygen and maintains mixing so aerobic
microorganisms can remain active and contact wastewater
contaminants.
9. Which condition generally indicates that an activated-sludge
aeration basin is receiving adequate oxygen for aerobic biological
treatment?
A. Complete absence of mixing
B. Adequate dissolved oxygen maintained throughout the aeration
process
C. Zero microbial activity
D. Continuous sludge flotation
D Exam Practice Questions And
Correct Answers (Verified Answers)
Plus Rationale 2027 Q&A| Instant
Download Pdf.
1. Which statement best describes the primary purpose of a
wastewater treatment facility?
A. To produce potable drinking water
B. To increase the hydraulic capacity of a sewer system
C. To remove or reduce pollutants so wastewater can be discharged
safely and protect public health and the environment
D. To eliminate the need for wastewater collection systems
The fundamental purpose of wastewater treatment is to reduce
physical, chemical, and biological pollutants before treated wastewater
is discharged or otherwise managed.
2. Which wastewater characteristic refers specifically to the amount
of oxygen microorganisms require to biologically decompose
biodegradable organic matter?
,A. Total dissolved solids
B. Biochemical oxygen demand (BOD)
C. Alkalinity
D. Turbidity
BOD indicates the amount of dissolved oxygen consumed by
microorganisms while stabilizing biodegradable organic material in
wastewater.
3. What is the principal function of a wastewater collection system?
A. Disinfect treated effluent
B. Remove dissolved nutrients
C. Transport wastewater from its source to a treatment facility
D. Digest wastewater sludge
Collection systems convey domestic, commercial, and other permitted
wastewater flows to treatment facilities for processing.
4. Which device is commonly used during preliminary wastewater
treatment to remove large floating and suspended debris?
A. Trickling filter
B. Secondary clarifier
C. Bar screen
D. Chlorine contact basin
Bar screens intercept large objects such as rags, sticks, plastics, and
other debris that could damage downstream equipment.
, 5. What is the primary purpose of grit removal?
A. Remove dissolved ammonia
B. Increase dissolved oxygen
C. Remove heavy inorganic particles such as sand, gravel, and grit
D. Destroy pathogenic organisms
Grit removal protects pumps and other equipment by removing dense
inorganic solids that can cause abrasion, clogging, and excessive
accumulation.
6. What is the main purpose of primary sedimentation?
A. Oxidize ammonia biologically
B. Remove settleable solids and some floating material by gravity
C. Disinfect wastewater
D. Increase wastewater temperature
Primary sedimentation allows heavier solids to settle and lighter
materials to float, reducing the solids and organic load entering
subsequent treatment processes.
7. Which treatment stage primarily uses microorganisms to remove
biodegradable organic matter from wastewater?
A. Screening
B. Grit removal
C. Secondary treatment
D. Preliminary treatment
, Secondary treatment relies primarily on biological processes in which
microorganisms consume and transform biodegradable organic
pollutants.
8. What is the primary function of an aeration basin in an activated-
sludge process?
A. Remove grit by gravity
B. Store disinfected effluent
C. Provide oxygen and mixing so microorganisms can biologically treat
wastewater
D. Concentrate screenings
Aeration supplies oxygen and maintains mixing so aerobic
microorganisms can remain active and contact wastewater
contaminants.
9. Which condition generally indicates that an activated-sludge
aeration basin is receiving adequate oxygen for aerobic biological
treatment?
A. Complete absence of mixing
B. Adequate dissolved oxygen maintained throughout the aeration
process
C. Zero microbial activity
D. Continuous sludge flotation
