What is the flow rate required to prevent solids from settling in the sewer line?

To prevent solids from settling in a sewer line, it's crucial to maintain an appropriate flow rate. A flow rate of 2.0 ft/sec is widely recognized as a threshold that helps ensure adequate scouring of the pipe, which is necessary to keep solids in suspension and prevent them from accumulating at the bottom of the pipe.

At this velocity, the flow can effectively mobilize particles and waste material, minimizing the risk of blockages and maintaining the health of the sewer system. If the flow rate drops below this level, as seen in other options, solids can begin to settle, creating conditions that lead to clogs and operational issues within the infrastructure. This makes 2.0 ft/sec the optimal choice to sustain a functional and efficient sewage transport system.