ABSTRACT
While a stepped spillway is a common design for energy dissipation purpose, aeration cascades are used for in-stream re-aeration, in water treatment plants to enhance the air-water transfer of atmospheric gases (e.g. oxygen, nitrogen) and for the removal of volatile organic components (VOC) such as methane and chlorine. The study presents new detailed characteristics of air-water flows, including interface area data, obtained in a large stepped cascade (25-m long, 0.5-m wide). A comparative analysis of air-water gas transfer rate on smooth-invert chute demonstrates that an aeration cascade is at least 10 times more efficient for re-oxygenation purposes.
