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:

The use of fine screens at the headworks in wastewater treatment plants has become very common. What is the typical average opening size of the screen?

A) 2 inches

B) 1 inch

C) 0.1 inch

D) 0.06 inch

Answer: 

The openings on the fine screens that are used for reducing solids and BOD are in the range of .04 to .25 inch (1 to 6 mm), with the average openings being 0.06 inch (1.5 mm). Therefore, the answer is D.

Source: WEF MOP 11 19-41

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.