碩士 / 國立高雄海洋科技大學 / 海洋環境工程研究所 / 104 / A practical method of treatment that is extensively used in environmental engineering is bioremediation, which degrades and transforms toxic pollutants to nontoxic or low-toxicity materials. This technique is commonly applied to treat oil pollution in the in-situ of factories. In order to improve remediation efficiency using biostimulation, this study investigates the mechanism that enhances the diesel-degradation efficiency of microorganisms in seawater. Using seawater samples collected from Kaohsiung, Taiwan, experiments on raising the diesel-degradation efficiency of microorganisms are conducted.
This study focuses on optimizing the cultivation conditions for diesel-degrading bacteria. Diesel fuel was added to seawater to simulate oil-polluted seawater. Batch cultures to which orange oil was added as a nutrient were used in the biostimulation experiment, whereas a sample without orange oil was used as the control group in the experiment. Seawater cultivation conditions were controlled at a pH of 8.1, salinity of 32.5 psu, and initial diesel fuel concentration of 17000 µg/ml; the concentrations of the orange oil added to the three groups was 4250(A sample), 1700(B sample), 850(C sample)µg/ml, and 425(D sample)µg/ml respectively. The temperature of the cultivation environment was controlled at 30°C, and cultivation was done at a spinning speed of 160 rpm.
The variations in the microorganism reproduction rate in the experimental samples were measured using the water-pH detection method and optical density measurements, whereas the degradation efficiency was obtained using the TPH-d detection method.
After 24 days, the concentration of the A sample decreased from 17000 to 15130µg/ml and 11% of diesel fuel was degraded. The B sample degraded to 11093 µg/ml and 34.8% of diesel fuel was degraded. The C sample degraded to 7265µg/ml and 57.3% of diesel fuel was degraded. The D sample degraded to 11830µg/ml and 31.4% of diesel fuel was degraded.
Furthermore, the control group degraded to 11830µg/ml and 30% of diesel fuel was degraded. The results revealed that the optimal concentration of orange oil for degrading diesel oil in oil-polluted seawater is 850 µg/ml.
A comparison between the effect of biostimulation on the degradation of marine diesel and general diesel showed that general diesel degraded from 17000 to 8500 µg/ml after 16 days and 50% of diesel fuel degraded, while marine diesel degraded to only 11223 µg/ml on the 16th day and 33% of diesel fuel was degraded. In summary, the growth and degradation performance of microorganisms decreased with increase in sulfur concentration in diesel fuel.
| Identifer | oai:union.ndltd.org:TW/104NKIM0282007 |
| Date | January 2016 |
| Creators | Yang,Shi-Jie, 楊士杰 |
| Contributors | Wu,Shiow-Shyan, 吳秀賢 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 73 |
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