Aeration efficiency influenced by venturi aerator arrangement, liquid flow rate and depth of diffusing pipes

Abstract

The effect of aerator module configuration, liquid flow rate and diffuser submergence on oxygen transfer efficiency was examined in a surface aeration system with venturi injectors using the clean water test. Six venturi aerator modules were evaluated and the results indicated that better aeration efficiencies could be achieved by simply changing the way the venturi aerators were connected. Among all the configurations examined (modules a–f), two and three aerators connected in parallel (modules d, e and f) were able to bring more oxygen into water than the others. An increase in liquid flow rate led to an enhancement of the oxygen transfer coefficients, but the improvement was reduced if the liquid flow rate was too high. The oxygen transfer coefficient was found to have a relationship with the depth of diffusing pipes (surface aeration depth) for the surface aeration system and an optimal depth of around 40 cm was obtained from this study.

Keywords:

• aeration depth
• liquid flow rate
• surface aeration
• oxygen transfer efficiency
• swine manure

Acknowledgements

This work was supported by the National Research Initiative Air Quality Program of the Cooperative State Research, Education, and Extension Service, US Department of Agriculture (No. 2006-55112-16639), the Innovative Research Team in Higher Educational Institutions of Zhejiang Province, P.R. China (No. T200912) and Zhejiang Provincial Natural Science Foundation of China (No.Y5110314).