| Summary: | 碩士 === 中原大學 === 環境工程學系 === 105 === Air sparging combined with soil vapor extraction(AS/SVE) is a common technology for remediation of soil and groundwater contamination. There are some advantages of this technology, such as easy equipment installation and low cost. However, AS/SVE may not be suitable or effective for removing the pollutants with low volatility. It would take longer treatment schedule and higher cost. Therefore, in this study, a method was developed to enhance volatilization of LNAPLs through adding alcohol to remediate diesel-oil-contaminated groundwater. According to the co-volatilization theory, the higher concentration and the higher carbon ranges of alcohol causes more volatility of organic compounds. In addition, a number of researches indicated soil organic matter content would adsorb organic vapor and reduce the volatilization from AS/SVE system. The influence of above-mentioned conditions would be examined.
In this study, a 3-D model was equipped to simulate AS/SVE remedial technology. The experiment period was set from 1 to 48 hours based on the volatility of each chemical. The organic vapor was adsorbed by a commercial activated carbon tube. After experiment, the sorbent was extracted, and the sample was analyzed by gas chromatography. Three kinds of alcohol, n-pentanol, n-hexanol and n-heptanol, were selected to implement the experiments. The concentration of alcohol was 5 and 10 ppmv. Moreover, two kinds of soil with different organic matter content were used to examine the result. The target chemicals were alkanes with carbon ranges C9 to C14 and diesel fuel.
The results demonstrated the components of diesel fuel formed LNAPLs, floated on water table, were not affected by the addition of alcohol with low concentration in system. The volatility of LNAPLs didn’t be enhanced with the increasing concentration and carbon ranges of alcohol. The results were not stable since the migration of LNAPLs in 3-D model and the effect on volatilization by residual chemical from last batch. The volatilization inhibition of LNAPLs by the soil with high organic matter content was not significant. It resulted from the preferential flow caused by the crack of soil.
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