Question 4002 of 234 · California Wastewater Operator Exam
The purpose of returning activated sludge (RAS) from the secondary clarifier to the aeration tank is to
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Correct answer to question 4002
- B: maintain a population of microorganisms in the aeration tank
Explanation
RAS brings active microorganisms back to the incoming wastewater so food can be consumed. Without RAS the biomass would wash out of the system.
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