| Summary: | 碩士 === 大葉大學 === 環境工程學系碩士班 === 93 === The activated sludge process is often used by environmental engineers for treating organic pollutants. If the target is a man-made organic matter that is persistent, the indigenous microorganisms need a stage of acclimation before they can display a degradation capability. In batch-mode reaction, the sludge and the target pollutant can be given sufficient contact time to complete an acclimation. On the other hand, in a continuous-flow reactor the sludge only has a time of about the mean-cell-residence-time (θc) to be in contact with the incoming substrate. This study was to perform continuous activated sludge experiments in which periodic loadings of a persistent xenobiotic 2,4-D were applied, after some down times during which a glucose feed was maintained. The results showed that: (1) when θc is too short, 2,4-D degradation ability was insufficiency; (2) when an down time of 2,4-D loading is smaller than θc, the sludge could still maintain the good 2,4-D degradation capability, which was improved by consecutive number of up time 2,4-D loadings; (3) when a down time was larger than θc by far, the sludge’s degradation capability diminished as a result of its replacement by generations grown from the glucose feed.
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