When faced with a licensing exam, don't struggle with test anxiety! Use the question below and others from our Exam Study Guide series to properly study and prepare for exam questions. Take a look at this sample wastewater treatment licensing question along with an explanation of the correct answer.

Sample question:

What is the recommended velocity of the flow in an oxidation ditch?

A) 0.1 to 0.5 feet/second

B) 0.8 to 1.2 feet/second

C) 1.5 to 2.0 feet/second

D) 2.5 to 4.0 feet/second

Answer: In the design of oxidation ditches, the mixed liquor is moved at a velocity of 0.8 to 1.2 ft/sec (0.24 to 0.37 m/s) in the channel which will result in a circuit time of less than 15 minutes. So, the answer is B.

Source: WEF MOP11 20-15

About the author
Ricky Lallish is the Water Pollution Control, Program Director at the Environmental Resources Training Center of Southern Illinois University Edwardsville. He provides training for entry level operators in the wastewater field and operators throughout the state looking to further their education.