The oxygen profile procedure is a means of measuring the oxygen concentration at various locations in a basin. By dividing the surface of a basin into sections and then establishing sample points on the surface, at mid-depth, and near the bottom, a waste water treatment plant operator can measure and plot dissolved oxygen data which can be plotted to visually show oxygen concentrations throughout the basin. Designed for individuals who have completed National Pollutant Discharge Elimination System (NPDES) level 1 laboratory training skills, this module provides operators with the basic skills and information needed to: (1) successfully run the oxygen profile test; (2) record data; (3) graph results; (4) interpret information in terms of recognizing areas of oxygen deficiency in the system being tested; and (5) obtain reliable, consistent results. The instructor's manual contains a statement of instructional goals, lists of instructor/student activities and instructional materials, narrative of the slide/tape program used with the module, overhead transparency masters, and student worksheet (with answers). The student workbook contains objectives, prerequisite skills needed before the module is started, laboratory procedures, and worksheet. (Author/JN)