This unit on aerobic sludge digestion covers the theory of the process, system components, factors that affect the process performance, standard operational concerns, indicators of steady-state operations, and operational problems. The instructor's guide includes: (1) an overview of the unit; (2) lesson plan; (3) lecture outline (keyed to a set of slides designed for use with the unit); (4) narrative for the slide program; (5) overhead transparency masters; (6) student worksheet (with answers); and (7) two copies of a final quiz (with and without answers). (JN)