HR: 1340h
AN: H13I-1418    [Abstracts]
TI: Power Law Tailing in Air-Sparging in Laboratory Scale Column Experiments
AU: * Kawanishi, T
EM: kawanisi@t.kanazawa-u.ac.jp
AF: Kanazawa University, Kakuma-machi, Kanazawa, 920-1192 Japan
AU: Sakami, A
H13I-1418 AF: Kanazawa University, Kakuma-machi, Kanazawa, 920-1192 Japan
AU: Ninagawa, K
H13I-1418 AF: Kanazawa University, Kakuma-machi, Kanazawa, 920-1192 Japan
AU: Hayashi, Y
H13I-1418 AF: Kanazawa University, Kakuma-machi, Kanazawa, 920-1192 Japan
AB: We carried out a series of laboratory scale column experiments of air-sparging in which carbon dioxide tracer was first saturated in the water filled in the glass bead column and then purged by pure nitrogen. The changes in carbon dioxide at the gas outlet were investigated and we found that the carbon dioxide concentration change obeyed power law rather than exponential. We consider that this is due to the power law distribution of the distance that a solute has to travel by diffusion from somewhere in the water to get to the air-water interface. We also constructed a model to analyze the distribution of the diffusion distances. The model successfully explained the power law behavior of the tracer concentration. What is significant here is that the column of glass bead of equal diameter, usually considered as a kind of uniform media, can reveal a heterogeneous behavior: due to the nature of the shape of gas flow path, which we consider is fractal like. We also investigated the reproducibility of the phenomena, effect of the flow rates, and the characteristics of the tracers, and the factors controlling the exponents of the power low behavior was discussed.
DE: 1829 Groundwater hydrology
DE: 1875 Vadose zone
SC: Hydrology [H]
MN: Fall Meeting 2005