Nevada Wastewater Treatment Plant Operator
Grade II Exam Questions And Correct Answers
(Verified Answers) Plus Rationales 2026 Q&A |
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1. The primary purpose of a wastewater treatment plant is to
a) Generate electricity
b) Produce drinking water
c) Remove pollutants from wastewater before discharge
d) Increase sewage volume
Rationale: The main goal of a wastewater treatment plant is to
protect public health and the environment by removing harmful
contaminants from sewage.
2. The most common method of primary treatment is
a) Filtration through sand
b) Sedimentation in a settling tank
c) Chemical oxidation
d) Biological aeration
Rationale: Primary treatment typically removes solids through
physical settling in clarifiers or sedimentation tanks.
3. BOD stands for
a) Biological Oxidation Demand
b) Biochemical Organic Density
c) Biochemical Oxygen Demand
d) Biological Oxygen Density
, Rationale: BOD measures the amount of oxygen microorganisms
require to decompose organic matter in water.
4. Which microorganism is most commonly used in activated sludge
processes?
a) Viruses
b) Protozoa
c) Bacteria
d) Fungi
Rationale: Bacteria are primarily responsible for breaking down
organic matter in activated sludge systems.
5. The main function of a clarifier is to
a) Aerate wastewater
b) Separate solids from liquid
c) Remove nutrients
d) Disinfect water
Rationale: Clarifiers allow solids to settle so that the clarified liquid
can move to secondary treatment.
6. Nitrification in wastewater treatment converts
a) Ammonia to nitrate
b) Nitrite to ammonia
c) Ammonia to nitrate through nitrite
d) Nitrate to nitrogen gas
Rationale: Nitrifying bacteria oxidize ammonia to nitrite, then
nitrite to nitrate.
7. Denitrification occurs under
a) Aerobic conditions
b) Anoxic conditions
, c) Hypoxic conditions
d) High temperature conditions
Rationale: Denitrification is a process where bacteria convert
nitrate to nitrogen gas in the absence of dissolved oxygen.
8. The main purpose of chlorination in wastewater treatment is to
a) Reduce solids
b) Disinfect effluent
c) Remove nutrients
d) Increase oxygen levels
Rationale: Chlorine is used to kill pathogenic organisms in treated
wastewater.
9. Which of the following is a common indicator of organic pollution
in water?
a) pH
b) BOD
c) Turbidity
d) Chloride
Rationale: BOD indicates the amount of organic matter that can
be biologically decomposed.
10. The unit process that uses microorganisms to remove
dissolved organics is called
a) Coagulation
b) Secondary treatment
c) Tertiary treatment
d) Screening
Rationale: Secondary treatment primarily relies on biological
processes to degrade dissolved and suspended organic matter.
Grade II Exam Questions And Correct Answers
(Verified Answers) Plus Rationales 2026 Q&A |
Instant Download Pdf
1. The primary purpose of a wastewater treatment plant is to
a) Generate electricity
b) Produce drinking water
c) Remove pollutants from wastewater before discharge
d) Increase sewage volume
Rationale: The main goal of a wastewater treatment plant is to
protect public health and the environment by removing harmful
contaminants from sewage.
2. The most common method of primary treatment is
a) Filtration through sand
b) Sedimentation in a settling tank
c) Chemical oxidation
d) Biological aeration
Rationale: Primary treatment typically removes solids through
physical settling in clarifiers or sedimentation tanks.
3. BOD stands for
a) Biological Oxidation Demand
b) Biochemical Organic Density
c) Biochemical Oxygen Demand
d) Biological Oxygen Density
, Rationale: BOD measures the amount of oxygen microorganisms
require to decompose organic matter in water.
4. Which microorganism is most commonly used in activated sludge
processes?
a) Viruses
b) Protozoa
c) Bacteria
d) Fungi
Rationale: Bacteria are primarily responsible for breaking down
organic matter in activated sludge systems.
5. The main function of a clarifier is to
a) Aerate wastewater
b) Separate solids from liquid
c) Remove nutrients
d) Disinfect water
Rationale: Clarifiers allow solids to settle so that the clarified liquid
can move to secondary treatment.
6. Nitrification in wastewater treatment converts
a) Ammonia to nitrate
b) Nitrite to ammonia
c) Ammonia to nitrate through nitrite
d) Nitrate to nitrogen gas
Rationale: Nitrifying bacteria oxidize ammonia to nitrite, then
nitrite to nitrate.
7. Denitrification occurs under
a) Aerobic conditions
b) Anoxic conditions
, c) Hypoxic conditions
d) High temperature conditions
Rationale: Denitrification is a process where bacteria convert
nitrate to nitrogen gas in the absence of dissolved oxygen.
8. The main purpose of chlorination in wastewater treatment is to
a) Reduce solids
b) Disinfect effluent
c) Remove nutrients
d) Increase oxygen levels
Rationale: Chlorine is used to kill pathogenic organisms in treated
wastewater.
9. Which of the following is a common indicator of organic pollution
in water?
a) pH
b) BOD
c) Turbidity
d) Chloride
Rationale: BOD indicates the amount of organic matter that can
be biologically decomposed.
10. The unit process that uses microorganisms to remove
dissolved organics is called
a) Coagulation
b) Secondary treatment
c) Tertiary treatment
d) Screening
Rationale: Secondary treatment primarily relies on biological
processes to degrade dissolved and suspended organic matter.
