Treatment Plant Operator Exam Study Guide Answers

A ping-pong ball travels from manhole A to manhole B 200 feet away in 1.5 minutes. The sewer line is a 6-inch sewer main. The line is running full. What is the velocity in this sewer main? Bonus: Is it within recommended speed? The answer to this question is C, 2.22 feet per second. This can be solved using the Velocity formula below. The velocity of flow in collection systems is an important fact to know. If the flow is too slow (below 1.5 feet per second) the solids (organic and inorganic) may settle out and cause septicity or hydrogen sulfide