Exam Study Guide: Trickling Filter Conditions; and Pumping Conditions

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 Nutrient Removal Bacteria; and Chemical Feed Pumps. This time, you can test your knowledge about trickling filter conditions; and pumping conditions.

Wastewater Treatment Sample Question

What condition on a trickling filter is caused by excessive organic loading, accumulation of debris such as trash or leaves or excessive algae growth?

A. Denitrification
B. Filamentous overgrowth
C. Filter flies
D. P

Answer: The answer to the question is D. Ponding is a very common condition on trickling filters. Excessive organic loading (resulting in rapid growth of biomass and large sloughing), accumulation of debris and leaves (generally from poor or neglected housekeeping) and/or excessive algae growth cause it. Each of these conditions results in poor performance and inadequate treatment. This is important to know for troubleshooting or general trickling film process control.

Water Treatment Sample Question

A pumping condition where the water level is below the eye of the impeller is referred to as:

A. Suction head condition.
B. Suction lift condition.
C. Discharge head condition.
D. D
ischarge lift condition.

Answer: The correct answer is B. Suction lift is not a preferred installation because of the increases in energy required to lift water to the eye of the impeller. In other words, the pump has to provide energy to move water on the suction side and discharge side, whereas a suction head condition has a positive head pressure from the water level on the suction side being higher than the eye of the impeller.

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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