好氧生物顆粒之氧氣擴散係數

Diffusivity of oxygen in aerobic granules

邱荏超(Ren-Chao Chiou)

指導教授 ： 李篤中

國立臺灣大學/工學院/化學工程學研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.01746

摘要

本論文中，藉由微電極儀器去量測好氧顆粒DO反應數據，並利用適合的質傳方程式去求解擴散係數。因實驗樣品不同，分為兩部分討論。第一部分，量測反應活性較小的兩種好氧顆粒，分別為貯存於4oC冰箱數個月的醋酸及酚好氧顆粒。生物外觀上觀察，可明顯看出醋酸好氧顆粒的粒徑大於酚好氧顆粒。在較高的水流流速通過好氧顆粒，減少表面質傳阻力至忽略。一維無反應質傳方程式，進行估算可發現，直徑對擴散係分為兩區：較大顆粒的醋酸好氧微顆粒，1.28-2.50 mm，具有較大的擴散係數1.24-2.28 x10-9 m2 s-1 ;較小顆粒的酚生顆粒，0.42-0.78 mm，具有較小的擴散係數2.50-7.65 x10-10 m2 s-1。
　　藉由微電極及雷射共軛焦顯微鏡量測，可發現好氧顆粒內部為層狀結構。穏態酚生顆粒內溶氧濃度數據說明好氧顆粒之表層具有高反應活性。考慮內部平均氧氣濃度做為邊界可求出擴散係數為1.34-1.82x10-9 m2 s-1。同時處慮非穏態及態態的溶氧數據可知，醋酸好氧顆粒表層之擴散係數為0.6-1.3x10-9 m2s-1；而酚好氧顆粒則為2.5-4.6x10-10m2s-1。由實驗結果顯示，反應及擴散圴為好氧顆粒內部氧氣傳輸的限制因素。

關鍵字

生物顆粒

並列摘要

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.

並列關鍵字

granule

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