This manual contains 17 instructional units (sequenced to correspond to parallel chapters in a student's manual) focusing on upgrading the design of wastewater plant facilities and serving as a reference source for establishing criteria for upgrading wastewater treatment plants. The manual also furnishes information for modifying plant design to compensate for current organic and hydraulic overloads and/or to meet more stringent future treatment requirements, emphasizing the importance of modifying existing plants and designing new plant facilities to accommodate operations, maintenance, and other routine plant functions. Each instructional unit contains title page, lesson plan, objectives, index to visual aids, and presentation guide. Topics considered include: field experience--designing for operability; maximizing plant operations feedback; plans and specifications reviews; general design considerations; unit process designs (headworks, primary sedimentation, aeration basins, secondary sedimentation, disinfection, effluent discharge, sludge treatment, other biological processes, and other factors--safety, energy conservation and emergencies); systems approach to unit process selection; equipment selection and placement for operability (flexibility and maintainability); and "an operator speaks to the design engineer." (Author/JN)