What is the typical effect of increasing the aeration time in an activated sludge basin?

What is the typical effect of increasing the aeration time in an activated sludge basin?

• A. No effect on treatment performance
• B. Increase in dissolved oxygen and improved BOD removal but higher energy consumption
• C. Lower energy costs due to more efficient mixing
• D. Immediate stoppage of biological activity

Answer: (B)

Increasing aeration time in an activated sludge basin gives microbes more time to use the supplied oxygen to oxidize organic matter. With more oxygen available over a longer period, biological treatment improves, so dissolved oxygen may rise to support sustained microbial activity and more complete BOD removal. The trade-off is energy use: running the aerators longer consumes more electricity, so while performance improves, energy costs go up. This is why longer aeration is generally associated with better treatment but higher energy consumption.

Increasing aeration time in an activated sludge basin gives microbes more time to use the supplied oxygen to oxidize organic matter. With more oxygen available over a longer period, biological treatment improves, so dissolved oxygen may rise to support sustained microbial activity and more complete BOD removal. The trade-off is energy use: running the aerators longer consumes more electricity, so while performance improves, energy costs go up. This is why longer aeration is generally associated with better treatment but higher energy consumption.