Effects of different in situ chemical oxidation (ISCO) on soil microorganisms and diesel degradation efficiency

• Main Authors: Chen-Ting Tang, 湯振廷
• Other Authors: Ku-Fan Chen
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/45996296814793645419

碩士 === 國立暨南國際大學 === 土木工程學系 === 102 === In this study, the effects of different in situ chemical oxidation (ISCO) on soil microorganisms and the efficiency of diesel degradation by different ISCO were evaluated by batch experiments. Results of the batch experiments indicate that the inhibition of double-stranded deoxyribonucleic acid (dsDNA) under different concentrations of oxidants (1% and 3% of persulfate, permanganate and hydrogen peroxide) were persulfate > hydrogen peroxide > permanganate. Significant decrease of dsDNA occurred with the addition of 3% persulfate and the recovery of dsDNA was not observed during 60 days of incubation due to the low pH values caused by persulfate. Although the addition of 3% hydrogen peroxide caused rapid inhibition of dsDNA at the beginning of the batch experiments, the amounts of dsDNA gradually recovered after 1 day of reaction. The growth of microorganisms with the addition of 3% permanganate was much better than that of persulfate and hydrogen peroxide addition. However, permanganate still caused adverse impacts on the growth of indigenous microorganisms. The inhibition of dsDNA by the selected oxidants under different activated/catalytic conditions was: heat activation (40 oC) > chelated-Fe(II) activation > Fe(II) activation > unactivation. Results of TPH degradation by persulfate and permanganate under different conditions show the removal of TPH increased due to the activation and high temperatures during 15 days of reaction. However, total removal efficiency of TPH was quite similar by the end of the batch experiments since the oxidants also consumed rapidly. Results also reveal the presence of ferrous ions were more persistent with the addition of chelating agent. The effects of different catalytic conditions on TPH removal were not significant due to the rapid consumption of hydrogen peroxide. The release of dissolved organic matter (DOM) was significant increased with the addition of the three oxidants under different environmental conditions. In addition, concentrations of DOM increased with increasing oxidant concentrations. Results of this study will be helpful to design practical systems using chemical oxidation coupled with bioremediation to remediate petroleum hydrocarbon-contaminated sites.