Abstract: A method and apparatus for clarifying liquids contaminated with suspended materials that do not readily separate by gravity, is disclosed. A flowing stream of the contaminated liquid is initially passed to a mixing zone at a predetermined flow velocity and intimately mixed with a gas stream to form a multiphase liquid-contaminant-gas stream. The flow velocity of the multiphase stream is then alternately increased and decreased with substantially simultaneous decrease and increase of pressure to ultimately disperse and dissolve the gas stream throughout the liquid and contaminant phases of the stream.