This manual was prepared by experienced wastewater treatment plant operators to provide a home study course to develop new qualified workers and expand the abilities of existing workers. The objective of this manual is to provide the knowledge and skills necessary for certification. Participants learn the basic operational aspects of treatment plants and the information necessary to analyze and solve operational problems. Each of the chapters begins with an introduction and then discusses start-up, daily operation and interpretation of lab results. Topics discussed include maintenance, safety, sampling, laboratory procedures, hydraulics, records, analysis and presentation of data, and report writing. Each lesson contains discussion and review questions and is completed with an objective test. (CS)