The occupational analysis contains a brief job description for the waste water treatment occupations of operator and maintenance mechanic and 13 detailed task statements which specify job duties (tools, equipment, materials, objects acted upon, performance knowledge, safety considerations/hazards, decisions, cues, and errors) and learning skills (science, mathematics/number systems, and communications). The 13 task statements cover the following performance duties: screening and comminuting, grit removal, pumping, flow measurement, pretreatment by chemical addition, coagulation and flocculation, sedimentation and primary and secondary solids removal, sludge wasting and digestion, biological decomposition through sludge process (contact stabilization, step aeration, conventional activated sludge, and extended aeration), biological decomposition through trickling filters, biological decomposition through oxidation lagoons/ponds (flucculative, aerobic, and anaerobic), chlorination, and outfall evaluation. The analysis also includes an appendix containing behavioral science objectives, a list of tools needed to perform each of the two jobs, and a glossary of terms. (JR)