Ontario Operator-in-Training (OIT) Practice Exam

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Study for the Ontario Operator-in-Training (OIT) Test. Use flashcards and multiple-choice questions for preparation, with hints and explanations for each. Get ready for your exam!

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Why is a minimum wastewater velocity of 0.6 m (2.0 feet) per second necessary in a gravity sewer?

To ensure optimal flow rate
To prevent the build up of solids in the sewer
To enhance odor control
To reduce environmental impact

The correct answer is: To prevent the build up of solids in the sewer

A minimum wastewater velocity of 0.6 m (2.0 feet) per second is essential in a gravity sewer primarily to prevent the build-up of solids within the sewer system. When wastewater flows at an adequate velocity, it helps to keep suspended solids in motion, reducing the likelihood of sediment settling at the bottom of the sewer line. If the flow rate drops below this threshold, solids can accumulate, leading to blockages or the formation of septic conditions that can contaminate the surrounding environment and cause unpleasant odors. Furthermore, maintaining this velocity is crucial for maintaining the overall efficiency of the sewer system, as it ensures that the wastewater is transported effectively to treatment facilities. The importance of preventing solids build-up directly contributes to the longevity and operational integrity of the sewer infrastructure, making it a fundamental principle in wastewater management.