Exam Study Guide: Bar Screen Knowledge

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When operators are faced with licensing exams, they sometimes struggle with test anxiety because they don’t understand how to study and prepare for exam questions. Here, we take a look at a sample wastewater treatment licensing exam question and explain the correct answer.

Bar screens typically have spacing of about:

A.  3 to 4 inches.
B.  3/8 to 2 inches.
C.  2 to 3 inches.
D.  4 to 6 inches.

Bar screens are primarily in place to screen non-organic waste debris from the wastewater flow. This includes, paper products, cigarette butts, napkins, condoms and inflow debris such as trash or storm debris that may have infiltrated into the collection system. Removing these items is a critical component with a conventional wastewater facility — and even with basic treatment techniques such as lagoons and oxidation ditches — to prevent these solids from entering the biological process. 

Typical disposal is simply dewatering and transferring them to a local landfill as this waste does not have an reuse value. The screens cannot be too small, or they'll restrict the flow because of rapid plugging from the volume of solids. And they can't be too large to allow unwanted debris from passing onto the next phase of the treatment process.

Therefore, the answer is "B," 3/8 to 2 inches.

About the Author
Mike Smith is program coordinator and lead faculty of the Water Quality Management program at Red Rocks Community College in Lakewood, Colo.

He has been in charge of the multi-faceted training program since 1996.


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