A new type of coarse media flocculator, using buoyant media instead of the heavier gravel in order to facilitate cleaning, was evaluated in laboratory and field studies. The results indicate that a two-stage buoyant coarse media (BCM) flocculator provided effective treatment at higher loading rates and shorter residence times than are typically employed in designing mechanical flocculators. Source-water quality and coagulant chemistry directly influenced flocculator performance and dictated the type of flocculator configuration selected. Tapering velocity gradients in the first-stage flocculator enhanced performance. The authors recommend that additional studies be performed to develop reliable design and operating criteria for full-scale BCM flocculators. Includes 11 references, tables, figures.