What effect does decreased velocity in sewer lines have on solids?

Decreased velocity in sewer lines leads to conditions that allow solids to settle out of the flow. When the velocity of wastewater flow is reduced, the kinetic energy of the particles is not sufficient to keep them suspended in the flow. As a result, heavier solids, such as grit, sediment, and other larger particles, will begin to settle to the bottom of the sewer line. This settling can lead to a buildup of solids in the line, potentially resulting in blockages or reduced capacity for the sewer system. Understanding this mechanism is crucial for effective collection system maintenance and operation, as it influences the management of wastewater and prevents operational issues.