Texas Wastewater Class B Practice Exam

Settable solids are primarily characterized by their ability to settle out of a liquid when left undisturbed for a certain period of time. This characteristic is important in wastewater treatment, where the separation of solids from liquid is essential for effective processing and clarification of wastewater. The term "settable" implies that these solids can be identified and quantified based on their tendency to accumulate at the bottom of a container or tank under the influence of gravity.

In contrast, small particles that do not settle would be categorized differently as they remain suspended in the liquid. Settable solids typically include larger particles that can be removed from the liquid through sedimentation processes. Additionally, while materials such as sand, grit, and minerals do contribute to the overall solid content in wastewater, settable solids specifically refer to those that can form a sediment layer. Lastly, the generation of solids during combustion is related to a different process and does not apply to the characteristics of settable solids in the context of wastewater treatment.