Exam Study Guide: Pumping Fundamentals; and Operating Pressure

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 Sequencing Batch Reactors; and Testing Membrane Filtration Units. This time, you can test your knowledge about pumping fundamentals, and operating pressure.

Wastewater Treatment Sample Question

What pump should never be operated or started against a closed valve?

A. Centrifugal pump
B. Peripheral pump
C. Positive displacement pump
D. Screw-lift pump

Answer: The answer to the question is C, screw-lift pump. Basic operation and knowledge of pumps and pumping are fundamentals that should be understood by most operators. Positive-displacement pumps are ideally suited for the pumping of solids such as sludges. These are well suited for some chemical applications such as polymers, as well. Due to the tremendous pressure built up by the pump, operating a positive displacement pump must never be operated against a closed valve or in a dry condition very long or it may rupture and cause damage to the pump, pipes and valves. 

Water Treatment Sample Question

What membrane filtration process requires the least amount of operating pressure? 

A. Ultrafiltration
B. Reverse osmosis
C. Microfiltration
D. Nanofiltration 

Answer: The correct answer is C, microfiltration. Compared to UF, NF, and RO, microfiltration has the largest pore size openings, which requires less applied pressure for the water to pass through. Microfiltration is capable of removing contaminants 0.1 microns in diameter and greater and is an effective tool in removing sediment, algae, protozoa and some bacteria from contaminated water. Microfiltration can be applied as a pre-treatment for UF, NF and RO membranes or as a post-treatment for granular media filtration.

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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