This lesson was developed for a course in sludge treatment and disposal. The lesson describes the Porteous heat treatment method of sludge conditioning and compares that system to the Zimpro wet air oxidation process. The theory of heat treatment, system of components and functions, and concepts of operation are addressed in the lesson. The instructor's manual contains a brief description of the lesson, estimated time, instructional materials list, suggested sequence of presentation, required reading list, reference reading list, objectives, lecture outline, narrative of the slide/tape program used with the lesson, and student worksheet (with answers). The student workbook contains objectives, plant flow diagrams, glossary, discussion of heat treatment, references, and worksheet. (Author/JN)