What is a characteristic of Type II settling?

Type II settling is characterized by the involvement of flocculated particles. In this context, flocculation refers to the process where fine particles clump together to form larger aggregates, or flocs, which then settle out of the suspension more efficiently. This occurs because the flocculated particles typically exhibit a higher settling velocity than individual particles would due to their increased size and mass after aggregation.

In Type II settling, the interaction between particles often occurs because they have undergone coagulation or flocculation processes, which can be induced by chemical additives or natural processes in the water body. The result is a denser network of particles that allow for more effective sedimentation as compared to other types of settling.

This contrasts with other types of settling, where factors such as uniformity of particle size or reliance solely on gravitational forces could dominate the settling process. For example, rapid sedimentation typically relates to Type I settling, which is characterized by uniform particle sizes that fall freely under gravity without significant interaction. Hence, Type II settling's unique attribute is the incorporation of flocculated particles, which facilitates their efficient settling in various environmental engineering applications.