The objective of this work was to analyse the impact of different geometric and operating parameters on the alpha factor value for fine bubble aeration systems equipped with EPDM membrane diffusers. Measurements have been performed on nitrifying plants operating under extended aeration and treating mainly domestic wastewater. Measurements performed on 14 nitrifying plants showed that, for domestic wastewater treatment under very low F/M ratios, the alpha factor is comprised between 0.44 and 0.98. A new composite variable (the Equivalent Contact Time, ECT) has been defined and makes it possible for a given aeration tank, knowing the MCRT, the clean water oxygen transfer coefficient and the supplied air flow rate, to predict the alpha factor value. ECT combines the effect on mass transfer of all generally accepted factors affecting oxygen transfer performances (air flow rate, diffuser submergence, horizontal flow).
Research Article|April 01 2008
Prediction of alpha factor values for fine pore aeration systems
Water Sci Technol (2008) 57 (8): 1265-1269.
S. Gillot, A. Héduit; Prediction of alpha factor values for fine pore aeration systems. Water Sci Technol 1 April 2008; 57 (8): 1265–1269. doi: https://doi.org/10.2166/wst.2008.222
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