Exam Study Guide: Industrial Waste Treatment; and Backflow Control Devices

Maintaining your education is important, especially in a career that demands licensing exams. Prove you’re an expert operator by answering these questions and others from our Exam Study Guide Series.

Welcome back to TPO magazine's Exam Study Guide Series, which offers a pair of water/wastewater study questions with in-depth explanations of the answers. Last time, we covered a set of wastewater and drinking water treatment questions on the topics of Corrosive Gases; and Calculating Brake Horsepower. This time, you can test your knowledge about industrial waste treatment; and backflow control devices.

Wastewater Treatment Sample Question

What type of ponds are often used to treat strong industrial wastes?

A. Aerobic
B. Anaerobic 
C. Facultative
D. Mechanically aerated 

Answer: The answer to this question is B. Anaerobic ponds are most often used to treat strong industrial and agricultural wastes. Some are used for pretreatment as well. They are used to reduce wastewater strength and do not provide complete treatment. They are normally followed by a more conventional treatment method. Anaerobic ponds are void of any oxygen sources including nitrate or nitrite. Knowledge of many forms of wastewater treatment processes are important for the operator’s ongoing training and development.

Water Treatment Sample Question

What is the best backflow control device for protecting a potable water line from contamination?

A. Reduced-pressure-zone
B. Air gap
C. Double check
Vacuum breaker

Answer: The correct answer is B. An air gap provides a complete separation between potable water and a potential source of contamination. This complete separation must be at least two times the internal diameter of the potable supply line, but no less than one inch. However, it is not always possible to have a complete separation, so a reduced-pressure-zone assembly would be installed on the potable supply line if the potential contamination poses a health hazard to the public. 

About the authors: Rick Lallish is the Water Pollution Control program director at the Environmental Resources Training Center (ERTC) 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. Lallish was also named the 2017 Illinois Operator of the Year and 2018 president of the Illinois Association of Water Pollution Control Operators.

Drew Hoelscher is the program director of drinking water operations at the Environmental Resources Training Center in Edwardsville, Illinois.


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