Basic Wastewater Operator Practice Exam| Questions and answers| Already Graded 100% Pass| New 2026

Basic Wastewater Operator Practice Exam| Questions and answers| Already Graded 100% Pass| New 2026 What is the predominant organism in a healthy activated sludge treatment plant? A. Stalked ciliates B. rotifers C. nematodes D. amoebas A. Stalked Ciliates A composite sample must be? A. sporadically collected in the treatment plant B. taken at one time C. analyzed immediately D. representative and sub-samples time spaced over 15 minutes apart D. representative and sub-samples time spaced over 15 minutes apart What is the standard volume for a BOD sample bottle? A. 150 mL B. 200 mL C. 300 mL D. 500 mL c. 300 mL If you have a lime slurry feed line, what is the best valve to use? A. plug valve B. butterfly valve C. RPZ dual check valve D. gate valve A. plug valve 5. If you notice a predominance of rotifers in your activated sludge sample while looking at it under a microscope, what does this indicate? A. healthy sludge B. young sludge C. old sludge D. middle age sludge C. old sludge Calculate the BOD using the given information: Initial DO: 8.3 Final DO: 5.9 Milliliters of sample used: 2 a. 360 mg/L b. 210 mg/L c. 856 mg/L d. 36 mg/L a. 360 mg/L If your activated sludge plant begins to nitrify, what conditions would you expect to decrease?