The general purpose of the occupational analysis is to provide workable, basic information dealing with the many and varied duties performed in the waste water treatment mechanics occupation. The document opens with a brief introduction followed by a job description. The bulk of the document is presented in table form. Twelve duties are broken down into a number of tasks and for each task a two-page table is presented, showing on the first page: tools, equipment, materials, objects acted upon; performance knowledge (related also to decisions, cues and errors); safety--hazard; and on the second page: science; math--number systems; and communications (performance modes, examples, and skills and concepts). The duties include performance of: screenings and comminuting; grit removal; pumping; flow measurement; pretreatment by chemical addition; coagulation and flocculation; sedimentation; sludge wasting and digestion; biological decomposition via activated sludge, trickling filters, and oxidation lagoons; and chlorination. The document concludes with three appendixes covering work attitudes and desirable personal characteristics, a list of standard tools, and 40 pages of items used in wastewater treatment. (BP)