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Air transfer efficiency of packed saturators used in DAF
Author(s) -
Steinbach Sandra,
Haarhoff Johannes
Publication year - 1997
Publication title -
journal ‐ american water works association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.466
H-Index - 74
eISSN - 1551-8833
pISSN - 0003-150X
DOI - 10.1002/j.1551-8833.1997.tb08341.x
Subject(s) - mass transfer , mass transfer coefficient , saturation (graph theory) , packed bed , mechanics , structured packing , transfer efficiency , materials science , thermodynamics , chemistry , environmental science , mathematics , chromatography , physics , engineering , mechanical engineering , combinatorics
A mathematical model predicts how saturation pressure, hydraulic loading, and packing depth affect air transfer. A rational model that predicts the air transfer efficiency in the packing layer of dissolved‐air flotation saturators is described. The model is defined in terms of absolute air concentrations, assumes the Lewis‐Whitman two‐film theory, and uses the Onda correlations to estimate the mass transfer coefficient. A comprehensive method is proposed for experimentally determining the overall air transfer efficiency of an operating saturator. A series of experiments was performed to partition the overall transfer efficiency into the contributions of top and bottom end effects, of free fall of the water before it reaches the packing, and of the packing itself. The laboratory data show a close agreement of the theoretical model with the measured performance. The model is used to demonstrate the effects of the most important saturator design parameters on the concentration of precipitable air.