Basic Wastewater Operator Practice Exam Questions and Answers with Complete Solutions 2024

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? A. settling in clarifiers B. chlorine demand C. BOD effluent D. TSS in effluent - a. settling in the clarifiers How do you calibrate a chemical feed pump? A. by measuring the pump output B. using the SWAG method C. jar test D. with a microscope - A. by measuring the pump output What is the chemical formula for sulfuric acid? a. HNO3 b. HCl c. NaOH d. H2SO4 - d. H2SO4 What is the most common type of activated sludge package plants? a. extended aeration b. sequential batch reactor c. oxidation ditch d. bardenpho - a. extended aeration