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 MBR Treatment and Consumer Confidence Reports. This time you can test your knowledge about SVI calculations and flow rate calculations.
Wastewater Treatment Sample Question
What is the sludge volume index (SVI) of the following aeration basin, given the following data: a settleometer reading of 860 mL after 5 minutes, 730 mL after 10 minutes, 650 mL after 15 minutes, and 420 mL after 30 minutes; an aeration basin mixed liquor suspended solids reading of 2,100 mg/L; a return MLSS of 4,400 mg/L; an effluent TSS of 10 mg/L; and an influent TSS of 240 mg/L.
A. 95 mL/g
B. 166 mL/g
C. 200 mL/g
D. 347 mL/g
Water Treatment Sample Question
What scenario would provide the lowest flow rate in gallons per minute?
A. Water flowing at a velocity of 2.5 feet per second through a 2-inch diameter pipe.
B. Water flowing at a velocity of 1 foot per second through a 4-inch diameter pipe.
C. Water flowing at a velocity of 2 feet per second through a 3-inch diameter pipe.
D. Water flowing at a velocity of 5 feet per second through a 1-inch diameter pipe.
To see answers for both of the above questions, click this link.
About the authors: Rick 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. 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.
