as circular (more efficient) and rectangular (more residence time). The former type requires just 3 minutes. A particular circular DAF system is called "Zero speed", allowing quite water status then highest performances; a typical example is an Easyfloat 2K DAF system. The rectangular type requires 20 to 30 minutes. One of the bigger advantages of the circular type is its spiral scoop. Drinking water treatment Drinking water supplies that are particularly vulnerable to unicellular algal blooms, and supplies with low turbidity and high colour often employ DAF. After coagulation and flocculation processes, water flows to DAF tanks where air diffusers on the tank bottom create fine bubbles that attach to floc resulting in a floating mass of concentrated floc. The floating floc blanket is removed from the surface and clarified water is withdrawn from the bottom of the DAF tank. See also API oil-water separator Flotation process Industrial wastewater treatment Industrial water treatment List of waste-water treatment technologies Microflotation References External links Treatment and Disposal of Ship-Generated Solid and Liquid Wastes (REMPEC Regional Marine Pollution Emergency Response Centre for the Mediterranean Sea, Project MED.B4.4100.97.0415.8, April 2004) Flotation processes Water treatment Waste treatment technology