The document presents the results of a technology assessment of the Schreiber counter-current aeration system. As of the Fall of 1984, 44 plants utilizing the technology were either operating or under construction in the United States. The aeration process employs air diffusers mounted at the bottom of a rotating bridge in a circular aeration tank. The configuration is claimed to reduce energy costs by providing a higher oxygen transfer efficiency than alternate methods. Operating records at the counter-current aeration facilities in Carlisle and Hampden, Pennsylvania, and Claiborne County and Loudon, Tennessee were utilized to determine performance and energy requirements at these facilities. These records were supplemented by on-site measurements of air flows, power usage, and additional wastewater sampling.