Abstract: A process for increasing the efficiency of a primary clarifier in raw waste water clarification by reducing biological oxygen demand and suspended solids by the sequential addition upstream of the primary clarifier of: (1) a salt of a water soluble bi- or tri-valent metal and compositions or mixtures thereof, (2) fly-ash, and (3) a cationic surface active polymer composition comprising a branched, high cationic charge density containing and water soluble polymeric polyether amine solution at the primary clarifier and recovering the clarified effluent from the primary clarifier.