Diffusivity of oxygen in aerobic granules

• Main Authors: Ren-Chao Chiou, 邱荏超
• Other Authors: 李篤中
• Format: Others
• Language: en_US
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/69710127631636589368

碩士 === 國立臺灣大學 === 化學工程學研究所 === 94 === The dissolved oxygen (DO) concentration in aerobic granules were measured using microelectrodes, based on which the diffusivity of oxygen was thereby estimated. Considering granules of low bioactivity, the acetate-fed granules of size 1.28-2.50 mm exhibited diffusivity of 1.24-2.28 x10-9 m2 s-1; while phenol-fed granules of size 0.42-0.78 mm had diffusivities of 2.50-7.65 x10-10 m2 s-1. Based on confocal laser scanning microscope testing the interior of granules exhibited layered structure. The steady-state DO concentrations of phenol-fed granule were recorded, showing that oxygen had been depleted in the surface reacting layer of granule. The oxygen diffusivity inside this reacting layer was estimated 1.34-1.82x10-9 m2 s-1 by assuming an mean oxygen concentration. Considering both steady-state and transient DO responses, the acetate-fed granule had diffusivity of oxygen of 0.6-1.3x10-9 m2s-1, while the phenol-fed granules had diffusivity of 2.5-4.6x10-10m2s-1. Both reaction and diffusion limits the oxygen transport in aerobic granules.