Rectangular tank surface aerators: scale up criteria and energy conservation

Rao, AR and Kumar, Bimlesh (2006) Rectangular tank surface aerators: scale up criteria and energy conservation. In: International Journal of Environmental science and Technology, 3 (4). pp. 425-433.

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Abstract

Surface aeration experiments were conducted in two types of rectangular tanks of aspect ratios i.e., length to width ratio (L/W) of 1.5 and 2 and developed simulation equations to correlate the oxygen transfer coefficient, k and power number, $P_0$ with a parameter governing theoretical power per unit volume X. The parameter X is defined as equal to $F^{4/3}R^{1/3}$, where F and R are impellers’ Froude and Reynolds numbers respectively). Results have shown that the $P_0$ can not be simulated singularly with either Reynolds number, R or Froude number, F, which results in scale-effects; there appears to be a need to incorporate the effects of both F and R. It was found that $P_0$ is uniquely related to X for rectangular aeration tanks of both aspect ratios, however, such relationships are different depending upon the aspect ratios. It has been demonstrated that energy can be saved substantially if the aeration tanks are run at relatively higher input powers. It is also demonstrated that smaller sized tanks are more energy conservative and economical when compared to big sized tanks, while aerating the same volume of water, and at the same time by maintaining a constant input power in all the tanks irrespective of their size.

Item Type:	Journal Article
Publication:	International Journal of Environmental science and Technology
Publisher:	Iranian Society of Environmentalists (IRSEN) and Center for Environment and Energy Research and Studies (CEERS)
Additional Information:	Copyright of this article belongs to Iranian Society of Environmentalists (IRSEN) and Center for Environment and Energy Research and Studies (CEERS).
Keywords:	Froude number;Oxygen transfer coefficient;Power number;Power per unit volume;Reynolds number;Surface aerators;Water and wastewater treatment
Department/Centre:	Division of Mechanical Sciences > Civil Engineering
Date Deposited:	30 Oct 2006
Last Modified:	19 Sep 2010 04:32
URI:	http://eprints.iisc.ac.in/id/eprint/8892

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