Wastewater Treatment Operator Certification Test 1: Questions & Answers: Updated Solution

What is the methane content in a properly operation anaerobic digester? A) 30 to 35% by volume B) 1 to 2% by volume C) 65 to 70% by volume D) 15 to 20% by volume (Ans- C) 65 to 70% by volume (v.2 pg 158) What will the addition of chlorine gas do to the pH of wastewater? A) Moderately increase pH B) pH will not be affected C) Significantly increase the pH D) Decrease the pH (Ans- D) Decrease the pH (v.1 pg 349-350) What is the purpose of a Parshall flume? A) measure turbidity B) measure flowrate C) measure settling rate D) measure solids content (Ans- B) measure flowrate (v.1 pg 43) What is the typical removal efficiency of settable solids in a primary clarifier? A) 95 to 99% B) 40 to 60% C) 20 to 50% D) 10 to 15% (Ans- A) 95 to 99% (v.1 pg 129) Which of the following is true about pumping scum from a primary clarifier? A) Pumping scum is less problematic during colder weather. B) Scum rarely leads to plugged pipelines due to its viscous nature. C) Scum causes more piping problems than other substances pumped at a wastewater treatment plant. D) Scum causes the least amount of piping problems among all the substances pumped at a wastewater treatment plant. (Ans- C) Scum causes more piping problems than other substances pumped at a wastewater treatment plant. (v.2 pg 449) What might cause thick billows of white sudsy foam in the aeration tank? A) MLSS is too high B) Temperature in the aeration tank is