This student manual contains the textual material for a unit which focuses on the structural and operationally unique features of aerated lagoons. Topic areas discussed include: (1) characteristics of completely mixed aerated lagoons; (2) facultative aerated lagoons; (3) aerated oxidation ponds; (4) effects of temperature on aerated lagoons; (5) mechanical surface aerators; (6) diffused air aerator; (7) lagoon testing; (8) design considerations; (9) operational considerations; and (10) maintenance. A list of objectives, glossary of key terms, list of references, and student worksheet are included. This unit is heavily dependent upon information presented in the unit on facultative lagoons and the two units should be presented together. If it is necessary to present only aerated lagoons, material from the facultative lagoon unit should be referenced and students encouraged to read it ahead of time. (JN)