Class I Practice Exam Questions And

Kentucky Wastewater Treatment Operator Class I Practice Exam Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the primary purpose of a wastewater treatment plant?

a) To generate electricity

b) To remove pollutants from wastewater

c) To desalinate water

d) To store water

Rationale: The main function of a wastewater treatment plant is to

remove physical, chemical, and biological pollutants from sewage before discharge.

• Which of the following is a common indicator of organic pollution in

water? 1 / 4

a) Nitrate

b) Biochemical Oxygen Demand (BOD)

c) Phosphate

• pH

Rationale: BOD measures the amount of oxygen required by

microorganisms to decompose organic matter in water, indicating organic pollution levels.

• Which stage of wastewater treatment primarily removes settleable

solids?

a) Tertiary treatment

b) Primary treatment

c) Secondary treatment

d) Disinfection

Rationale: Primary treatment involves physical processes like

sedimentation to remove settleable solids from wastewater.

• What is the purpose of an aeration basin in secondary treatment?

a) Remove heavy metals

b) Promote microbial decomposition of organic matter

c) Settle suspended solids

d) Neutralize pH

Rationale: Aeration basins supply oxygen to microorganisms that digest

organic material in secondary treatment. 2 / 4

• Which of the following is a method of disinfection commonly used in

wastewater treatment?

a) Chlorination

b) Both A and C

c) Filtration

d) Sedimentation

Rationale: Disinfection removes pathogens from treated wastewater, and

common methods include chlorination and UV radiation.

6. Sludge thickening is designed to:

a) Remove pathogens

b) Reduce water content of sludge

c) Increase oxygen demand

d) Neutralize pH

Rationale: Sludge thickening reduces the volume of sludge by removing

excess water, making handling and processing more efficient.

• What is the primary function of a bar screen in wastewater treatment?

a) Remove dissolved solids

b) Remove large debris and trash

c) Neutralize pH

d) Reduce BOD

Rationale: Bar screens prevent large objects like rags, sticks, and plastics

from entering the treatment process. 3 / 4

8. Nitrification in wastewater treatment is:

a) Conversion of nitrate to ammonia

b) Conversion of ammonia to nitrate

c) Removal of phosphorus

d) Sedimentation of solids

Rationale: Nitrification is a biological process where ammonia is oxidized

to nitrite and then nitrate by bacteria.

• What type of microorganism is primarily responsible for BOD removal

in secondary treatment?

a) Viruses

b) Bacteria

c) Algae

d) Protozoa

Rationale: Bacteria decompose organic matter in wastewater, reducing

the BOD level.

• Which parameter is used to measure the strength of

wastewater?

• pH

b) BOD

c) Temperature

d) Turbidity

• / 4