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 Upstream Screening Requirements and Sample Preservation. This time you can test your knowledge about organic loading calculation and types of soil.
Wastewater Treatment Sample Question
Given the following data:
• Facultative lagoon 1,000 feet long x 500 feet wide x 8 feet deep at maximum depth
• Influent BOD 210 mg/l
• Effluent BOD 12 mg/l
• Influent TSS 310 mg/l
• Effluent TSS 18 mg/l
• Daily flow of 250,000 gallons
• Fecal Coliform limits of 400 cfu/daily max
This facultative lagoon is a controlled discharge and the lagoon is at 60% capacity. What is the organic loading of this lagoon?
A. 24 pounds per day per acre
B. 38 pounds per day per acre
C. 76 pounds per day per acre
D. 135 pounds per day per acre
Water Treatment Sample Question
What soil type is most likely to cause a cave-in during excavation work?
A. Type A
B. Type B
C. Type C
D. Stable Rock
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 (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.
