Influence of Chute Slope on Oxygen Content in Stepped Waterways

Year 2009, Volume: 22 Issue: 4, 325 - 332, 27.03.2010

Ahmet Baylar , M. Emıroglu Tamer Bagatur

Abstract

Water quality and its enhancement have a close connection with the presence of dissolved oxygen. In fact, the oxygen concentration in surface waters is a prime indicator of the water quality for human use as well as for the aquatic biota. The physical process of oxygen transfer or oxygen absorption from the atmosphere acts to replenish the used oxygen. This process is termed re−aeration or aeration. Aeration enhancement by macro−roughness is well−known in water treatment, and one form is the aeration cascade. The macro−roughness of the steps significantly reduces flow velocities and leads to flow aeration along the stepped cascade. This paper seeks influence of channel slope on oxygen content in stepped cascade aerators. It is demonstrated that the aeration efficiency of the stepped cascade aerators increases with increasing channel slope.

 

Key Words: Aeration efficiency, Oxygen transfer, Stepped waterway, Chute slope.

 

Keywords

Aeration efficiency, Oxygen transfer, Stepped waterway, Chute slope

References

• [1] Chanson, H., “The Hydraulics of Stepped Chutes and Spillways”, 1th edition, Balkema, Lisse, The Netherlands (2002).
• [2] Toombes, L., Chanson, H., “Air-water flow and gas transfer at aeration cascades: A comparative study of smooth and stepped chutes”, Proceedings of the International Workshop on Hydraulics of Stepped Spillways, Zurich, Switzerland, 22-24, 77- 84 (2000).
• [3] Essery, I.T.S., Tebbutt, T.H.Y., Rasaratnam, S.K., “Design of Spillways for Reaeration of Polluted
• Waters”. Rep. 72, CIRIA, UK (1978). [4] Chanson, H., Toombes, L., “Experimental study of gas-liquid interfacial properties in a stepped cascade flow”, Environmental Fluid Mechanics, 2(3): 241-263 (2002).
• [5] Emiroglu, M.E., Baylar, A., “An investigation of effect of stepped chutes with end sill on aeration performance”, Water Quality Research Journal of Canada, 38(3): 527-539 (2003).
• [6] Baylar, A., Emiroglu, M.E., “Study of aeration efficiency at stepped channels”, Proceedings of the Institution of Civil Engineers, Water and Maritime Engineering, 156(WM3): 257-263 (2003).