FREE Wastewater Operator Chemistry and Biology Questions and Answers

Question 1

What does Biochemical Oxygen Demand (BOD) measure?

Accepted Answer

The amount of oxygen needed by microorganisms to break down organic matter in water.

Answer

The amount of oxygen in the atmosphere.

Answer

The concentration of chlorine in treated wastewater.

Answer

The total suspended solids in wastewater.

Question 2

What is the typical pH range of wastewater suitable for biological treatment?

Accepted Answer

6.5 to 8.5

Answer

2.0 to 4.0

Answer

9.0 to 11.0

Answer

4.5 to 5.5

Question 3

What is the main purpose of nitrogen removal in wastewater treatment?

Accepted Answer

To prevent eutrophication in receiving water bodies.

Answer

To reduce sludge production.

Answer

To remove pathogens from the wastewater.

Answer

To lower the BOD levels in effluent.

Question 4

What role do microorganisms play in the activated sludge process?

Accepted Answer

They digest organic pollutants in wastewater.

Answer

They provide aeration for oxygen transfer.

Answer

They remove nutrients through chemical reactions.

Answer

They increase the alkalinity of the water.

Question 5

Which of the following is an example of a disinfection method used in wastewater treatment?

Accepted Answer

Chlorination

Answer

Aeration

Answer

Sedimentation

Answer

Biological filtration