Pass your wastewater certification exam the first time! This study guide is specially developed to give wastewater operators practice answering questions that are similar in format and content to the questions that appear on certification exams. Sample questions are provided for Classes I, II, III, and IV wastewater operator certification exams, so you can study the questions that are specific to your grade level. Answers and references are included for questions. Math questions include the method to solve.Table of Contents.