Oklahoma Wastewater Operator Class
B Exam Practice Questions And
Correct Answers (Verified Answers)
Plus Rationale 2027 Q&A| Instant
Download Pdf.
1. Which Oklahoma Department of Environmental Quality (DEQ)
certification level generally requires 100 hours of DEQ-approved
training or an approved equivalent and three years of waterworks
or wastewater works operating experience, including one year of
actual hands-on operating experience?
A. Class D
B. Class C
C. Class B
D. Class A
The Class B certification requirements include 100 hours of approved
training or an approved equivalent and three years of qualifying
operating experience, including one year of actual hands-on experience.
, 2. In a conventional activated-sludge wastewater treatment plant,
what is the primary purpose of returning a portion of settled
activated sludge from the secondary clarifier to the aeration basin?
A. To increase chlorine residual
B. To maintain an adequate concentration of microorganisms in the
aeration basin
C. To remove grit from influent wastewater
D. To reduce influent hydraulic loading
Return activated sludge maintains the biological population needed for
effective oxidation of biodegradable organic matter in the aeration
basin.
3. A wastewater operator observes that dissolved oxygen in an
aeration basin has fallen substantially below the plant's normal
operating range. Which condition is most likely to result if the
problem persists?
A. Increased nitrification efficiency
B. Improved sludge settling
C. Incomplete biological treatment and possible septic conditions
D. Immediate elimination of all microorganisms
Insufficient dissolved oxygen can impair aerobic microorganisms, reduce
treatment efficiency, promote undesirable anaerobic conditions, and
contribute to poor effluent quality.
, 4. What does biochemical oxygen demand (BOD) primarily measure in
wastewater treatment?
A. The concentration of suspended inorganic solids
B. The amount of chlorine required for disinfection
C. The oxygen consumed biologically while biodegradable organic
matter is stabilized
D. The alkalinity available for nitrification
BOD is an indirect measure of biodegradable organic material based on
the oxygen microorganisms consume while degrading that material.
5. A treatment plant receives an average flow of 2.0 MGD with an
influent BOD concentration of 250 mg/L. Approximately how many
pounds of BOD enter the plant each day?
A. 208 lb/day
B. 2,085 lb/day
C. 4,170 lb/day
D. 8,340 lb/day
The standard loading calculation is MGD × mg/L × 8.34, so 2.0 × 250 ×
8.34 equals approximately 4,170 lb/day.
6. Which process most directly removes settleable inorganic materials
such as sand, gravel, and grit from wastewater?
A. Chlorination
B. Activated sludge
, C. Grit removal
D. Sludge digestion
Grit removal is specifically designed to capture dense inorganic particles
before they enter downstream treatment processes where they could
cause abrasion and accumulation.
7. What is the principal function of a primary clarifier?
A. Oxidize ammonia to nitrate
B. Disinfect treated effluent
C. Remove settleable solids and floating materials from wastewater
D. Increase dissolved oxygen concentration
Primary clarification separates solids that can settle by gravity and
materials that float, reducing the organic and solids load on secondary
treatment.
8. Which operational measurement is particularly useful for evaluating
the concentration of activated sludge microorganisms in an
aeration basin?
A. Chlorine residual
B. Mixed liquor suspended solids (MLSS)
C. Influent temperature only
D. Effluent alkalinity only
B Exam Practice Questions And
Correct Answers (Verified Answers)
Plus Rationale 2027 Q&A| Instant
Download Pdf.
1. Which Oklahoma Department of Environmental Quality (DEQ)
certification level generally requires 100 hours of DEQ-approved
training or an approved equivalent and three years of waterworks
or wastewater works operating experience, including one year of
actual hands-on operating experience?
A. Class D
B. Class C
C. Class B
D. Class A
The Class B certification requirements include 100 hours of approved
training or an approved equivalent and three years of qualifying
operating experience, including one year of actual hands-on experience.
, 2. In a conventional activated-sludge wastewater treatment plant,
what is the primary purpose of returning a portion of settled
activated sludge from the secondary clarifier to the aeration basin?
A. To increase chlorine residual
B. To maintain an adequate concentration of microorganisms in the
aeration basin
C. To remove grit from influent wastewater
D. To reduce influent hydraulic loading
Return activated sludge maintains the biological population needed for
effective oxidation of biodegradable organic matter in the aeration
basin.
3. A wastewater operator observes that dissolved oxygen in an
aeration basin has fallen substantially below the plant's normal
operating range. Which condition is most likely to result if the
problem persists?
A. Increased nitrification efficiency
B. Improved sludge settling
C. Incomplete biological treatment and possible septic conditions
D. Immediate elimination of all microorganisms
Insufficient dissolved oxygen can impair aerobic microorganisms, reduce
treatment efficiency, promote undesirable anaerobic conditions, and
contribute to poor effluent quality.
, 4. What does biochemical oxygen demand (BOD) primarily measure in
wastewater treatment?
A. The concentration of suspended inorganic solids
B. The amount of chlorine required for disinfection
C. The oxygen consumed biologically while biodegradable organic
matter is stabilized
D. The alkalinity available for nitrification
BOD is an indirect measure of biodegradable organic material based on
the oxygen microorganisms consume while degrading that material.
5. A treatment plant receives an average flow of 2.0 MGD with an
influent BOD concentration of 250 mg/L. Approximately how many
pounds of BOD enter the plant each day?
A. 208 lb/day
B. 2,085 lb/day
C. 4,170 lb/day
D. 8,340 lb/day
The standard loading calculation is MGD × mg/L × 8.34, so 2.0 × 250 ×
8.34 equals approximately 4,170 lb/day.
6. Which process most directly removes settleable inorganic materials
such as sand, gravel, and grit from wastewater?
A. Chlorination
B. Activated sludge
, C. Grit removal
D. Sludge digestion
Grit removal is specifically designed to capture dense inorganic particles
before they enter downstream treatment processes where they could
cause abrasion and accumulation.
7. What is the principal function of a primary clarifier?
A. Oxidize ammonia to nitrate
B. Disinfect treated effluent
C. Remove settleable solids and floating materials from wastewater
D. Increase dissolved oxygen concentration
Primary clarification separates solids that can settle by gravity and
materials that float, reducing the organic and solids load on secondary
treatment.
8. Which operational measurement is particularly useful for evaluating
the concentration of activated sludge microorganisms in an
aeration basin?
A. Chlorine residual
B. Mixed liquor suspended solids (MLSS)
C. Influent temperature only
D. Effluent alkalinity only
