Tennessee Wastewater Operator Practice Exam

In an aerated grit basin, what parameter influences particle sinkage?

1. Density of the particles

2. Velocity of the flow pattern

3. Temperature of the water

4. pH level of the mixture

The correct answer is: Velocity of the flow pattern

In an aerated grit basin, the velocity of the flow pattern is a critical factor that influences how particles sink. When considering sedimentation processes, the flow velocity determines how effectively particles can settle to the bottom. If the flow velocity is too high, particles may remain suspended in the water column and fail to sediment; conversely, if the flow velocity is appropriately controlled, it allows for optimal settling of grit and suspended solids. A well-designed aerated grit basin ensures that the flow pattern facilitates the settling of heavier particles, such as sand and grit, while lighter organic materials may be kept in suspension. The manipulation of hydraulic conditions by adjusting the flow rate helps achieve this balance, maximizing the efficiency of sedimentation. By focusing on the velocity of the flow pattern, operators can effectively manage the basin's design and operation to ensure proper sedimentation of undesired materials, making this parameter essential for the functionality of the aerated grit basin.