Tennessee Wastewater Operator Practice Exam

What feature of aerobic digesters facilitates the easy removal of solids from the bottom?

1. Vertical walls

2. Sloped floor

3. Wide opening at the top

4. Gravity-fed outlet

The correct answer is: Sloped floor

The feature that facilitates the easy removal of solids from the bottom of aerobic digesters is the sloped floor. A sloped floor design promotes efficient movement of sludge towards the outlet or removal point. The slope uses gravity to assist in the accumulation and consolidation of settled solids, allowing them to flow more easily toward designated collection areas, such as hoppers or drains. This design helps prevent clogging and ensures that the solid waste can be collected and processed effectively. While vertical walls may provide structural integrity, they do not aid in the removal of solids. A wide opening at the top is useful for accessing the digester but does not directly influence the removal of settled solids at the bottom. A gravity-fed outlet is beneficial for controlling flow but relies on the prior effective movement of solids facilitated by the sloped floor. Thus, the design choice of having a sloped floor optimally aids in the operational efficiency of the aerobic digester by promoting effective solids removal.