Slurry Test Evaluation for In-Situ Remediation of TCE Contaminated Aquifer

Sharma, Sachin

Etd

Slurry Test Evaluation for In-Situ Remediation of TCE Contaminated Aquifer

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Trichloroethylene (TCE) is the most commonly found groundwater pollutant. The focus of this research was to determine the effectiveness of chemical oxidation for in-situ remediation of TCE contaminated aquifers. Analytical techniques were developed to measure the concentration of TCE and its degradation products in soil and in solution. Slurry tests were conducted to emulate in situ conditions. Various media used for the slurry tests included sand, silica and glass beads. In-situ chemical oxidation of the TCE was performed using sodium persulfate (Na2S2O8), Fentonâ€™s reagent, Ozone and sodium persulfate activated by iron, ozone and zero valent iron. Persulfate oxidation was shown to be effective for TCE oxidation in the presence of all the media tested in slurry tests for various molar ratios of oxidant and catalyst (Fe). Approximately 75% of TCE destruction takes place in the first 5 minutes of the slurry test and 90% destruction within 24 hours. Fentonâ€™s oxidation was tried with varying concentration of H2O2 and slurry volume. Percent removal of TCE decreased from a hydrogen peroxide concentration of 3.34% to 5% (w/v). It was found that persulfate oxidation activated by zero valent iron removed TCE more effectively than persulfate oxidation activated by ferrous iron. For persulfate oxidation activated by ozone it was found that 95% of TCE was destroyed at persulfate/TCE molar concentration of 10/1 with an initial rate constant of 0.2854/min. It was also found that increasing the amount of solids in the slurry test decreased the effectiveness of chemical oxidation.

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