ABSTRACT
T HOUGH screening, comminuting, and grit removal take away much of the wastestreams solids mass, after preliminary treatment the influent still contains suspended organic solids. These settleable organic and floatable solids are readily concentrated and removed by primarylplain sedimentation (or clarification) under relatively quiescent conditions (see Figure 15.1). Primary clarification can be expected to remove 90 to 95% of settleable solids, 40 to 60% of total suspended solids, and 25 to 35% of BOD5.
