Tennessee Wastewater Operator Practice Exam

An activated sludge process with a high oxygen uptake and slow settling rate indicates what about its condition?

1. Low food supply

2. High food supply

3. Excessive chemical additions

4. Oxygen depletion

The correct answer is: High food supply

In an activated sludge process, a high oxygen uptake typically suggests that the microorganisms present are actively metabolizing organic matter and consuming oxygen for respiration. This high oxygen demand indicates that there is a sufficient supply of food, or organic material, available for the microorganisms to utilize. A slow settling rate, on the other hand, can be associated with a population of microorganisms that may be less flocculent or that have lower density. This condition can contribute to challenges in separating the biomass from the treated water, but it does not negate the correlation between a high oxygen uptake and the presence of ample food supply. In summary, the right answer indicates that the microorganisms are thriving due to a high concentration of organic matter available, promoting high metabolic activity and oxygen consumption. This can often happen in environments where wastewater is rich in nutrients, which supports the growth of the microbial community involved in wastewater treatment.