| Summary: | 碩士 === 國立中興大學 === 環境工程學系 === 91 === Abstract
The main object of this research is to stimulate the methane oxidation in the cover soils of landfill by adding external carbon sources (methanol, ethanol, formic acid, acetic acid and glucose), then simulate the phenomenon of methane oxidation in batch experiments.Finally investigate the correlation of the rate of methane oxidation and the number of bacterium.
After adding carbon sources into the soils with 1、2、5 mg CH3OH/g dry soil and 1、2、5 mg Glu./g dry soil , the methane oxidation significantly increased. However, because of too much carbon dioxide cumulated, the soils after adding 10 mg CH3OH/g dry soil and 10 mg Glu./g dry soil became unfavorable environment for the methanotrophs. For the following experiments, we have exhausted the carbon dioxide cumulated in the flask bottle. From the result of experiments, we notice that the rate of methane oxidation in the soils of adding external carbon sources is faster than the blank.
The soils after adding formic acid or acetic acid would have low pH value, therefore reducing the activity of methanotrophs and becoming unfavorable environments for methane oxidation. The pH value in the soils after adding methanol and glucose remained within the neutral range, and the distribution of methanotrophs reached the number of 105 MPN/g dry soil. Therefore, we can conclude that the pH value of the most favorable landfill for the growing of methanotrophs is between 6.0-7.5.
The correlation coefficient (R2) between the number of methanotrophs and the speed rate of methane oxidation is high, and it is about 0.9. This result can be used for landfills to estimate the rate of methane oxidation based on and the number of methanotrophs afterward.
The blank soils in this research have a phenomenon of insufficient carbon sources. Adding methanol and glucose not only increases the methane oxidation in the soils, but also provides the needed carbon sources for the growth to maintain the activity. We can add external carbon sources in the soils of landfill to increase the quantity of organic compounds, so that to assure the methane oxidation to be efficient. Therefore, adding external carbon sources is an important practice for the growing of methanotrophs in the soils.
Keywords: Landfill, Carbon sources, Methane oxidation, Methanotrophs
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