Florida Wastewater Practice Test

What is the objective of wasting activated sludge?

1. Reduce sludge volume

2. Maintain a balance between microorganisms and incoming food

3. Increase aeration time

4. Remove toxic substances

The correct answer is: Maintain a balance between microorganisms and incoming food

Wasting activated sludge is primarily aimed at maintaining a balance between microorganisms and the available food, which is the organic matter present in the wastewater. This balance is crucial for the effective operation of the biological treatment process. When excess activated sludge is removed from the system, it reduces the overall concentration of microorganisms in relation to the organic load. This allows the remaining microorganisms to have enough food (substrate) to consume, facilitating efficient digestion of the incoming organic matter. If too few microorganisms are present, the treatment process may become less effective, leading to incomplete degradation of pollutants. By regularly managing the amount of activated sludge in relation to the inflow of food, operators can ensure optimal treatment conditions and maintain healthy microbial populations, which are essential for the biological treatment of wastewater. While reducing sludge volume is a byproduct of wasting, the primary goal remains focused on the balance of microorganisms and food to sustain proper biological activity in the system.