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 Waste Gas Burners and Identifying Blown Fuses. This time you can test your knowledge about repacking pumps, and pump current signals.

Wastewater Treatment Sample Question

What condition may occur if old packing is not removed completely before repacking a pump?

A. Tension-alignment problems
B. Shaft scoring 
C. Excessive leaking from the magnetic seal
D. Packing gland misalignment

Water Treatment Sample Question

What mA signal should an operator expect if the chemical feed pump is operating at 75% flow capacity on a 4 mA to 20 mA current loop? 

A. 4
B. 8
C. 16
D. 20

To see answers for both of the above questions, click this link.

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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.