Did you know that bubbles can clean water? Specifically, dissolved air flotation (DAF) and ultrasound are two methods of making water safer with bubbles. DAF can be used to replace sedimentation in municipal drinking water treatment. Large particles are typically settled out using gravity, but with DAF, bubbles are produced by an oxygen tank pumping air into the bottom of a basin and small particles attach to the sides of the bubbles. The bubbles rise to the top of the basin and the particles are swept off the surface of the water by a skimmer.