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 Wastewater Treatment Terminology and Water System Mandates. This time you can test your knowledge about population equivalent calculations and water filter head loss.
Wastewater Treatment Sample Question
We are problem-solving for population equivalent (PE). The city of Anytown is planning to add a new subdivision in the northwestern part of the city. The prospective subdivision is expected to be 324 residential multifamily units with an estimated 1,296 people moving in. There is no planned commercial or industrial development within this subdivision. The collection system will have one lift station and will be comprised of 8-inch sewer mains throughout. What is the expected population equivalent impact on the BOD levels in pounds added to the influent flow?
A. 12.96 lbs
B. 220.3 lbs
C. 259.2 lbs
D. 7623 lbs
Water Treatment Sample Question
When should a filter have the lowest headloss?
A. Several hours after the ripening stage
B. When the filter is experiencing air binding
C. Immediately after the filter backwash process
D. When a coagulant aid is overfed to enhance turbidity removal
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.
