For surface aerators, keeping the device less submerged will generally do what to oxygen transfer efficiency?

For surface aerators, keeping the device less submerged will generally do what to oxygen transfer efficiency?

• A. Decrease
• B. Increase
• C. No effect
• D. Depends on water temperature

Answer: (B)

When a surface aerator is less submerged, it creates more air at the water surface and enhances air–water contact. This boosts the interfacial area and promotes the formation of numerous small bubbles that dissolve oxygen more effectively, so the oxygen transfer efficiency goes up for the same energy input. If the device sits deeper, less air is entrained near the surface and energy is wasted moving water rather than improving air transfer, reducing efficiency.

When a surface aerator is less submerged, it creates more air at the water surface and enhances air–water contact. This boosts the interfacial area and promotes the formation of numerous small bubbles that dissolve oxygen more effectively, so the oxygen transfer efficiency goes up for the same energy input. If the device sits deeper, less air is entrained near the surface and energy is wasted moving water rather than improving air transfer, reducing efficiency.