The results of a 15-month experimental and analytical project to investigate and begin development of the U-tube aeration concept are presented. Three major tasks were accomplished: (1)Experimental verification of oxygen transfer efficiencies and exploration of practical aspects of U-tube operation; (2) analytical investigation of two major applications--post-aeration of effluent from a sewage treatment plant and in-situ aeration of sanitary sewer flows to prevent anaerobic conditions; (3) investigation and design of prototype U-tube systems, with particular emphasis on designs for installation in the Jefferson Parish, Louisiana sewer system. It was found that the U-tube is a practical, efficient method for aerating a moving water or waste water stream.