TCE로 오염된 토양의 동전기적 공법 적용에 관한 연구

Abstract

Trichloroethylene(TCE) used as a model contaminant in this research is a representative hazardous chlorinated organic compound and is widely used as an ingredient in the industrial cleaning solutions. As TCE has the higher density than water (i.e. DNAPL) and the relatively low partition coefficient in aqueous phase, it tends to be transported in the subsurface environment. Moreover as TCE is difficult to be degraded biologically, it remains extended time in the subsurface. On the contrary, due to the same properties it can be rapidly removed from the contaminated site in the early contamination stage. In this research, one-dimensional column experiments were carried out to understand the removal mechanism of TCE in the fine grained soil media. Firstly, a column experiment under the condition of 0.01A constant current was carried out as a reference experiment. To increase the electroosmotic flow and the TCE solubility in the aqueous phase, two experiments applying 0.03A constant current or 0.01 M NaOH purging solution as a pH buffer and one experiment applying 20% methanol purging solution as a cosolvent were carried out, respectively. In addition, to explain the retardation of TCE transport in the clayey soil, the batch adsorption tests were conducted with pH 4, 7, 12 and 20% methanol solution. The results showed that the residual concentrations of TCE were not detected in the soil specimen with the 20% methanol experiment and the other experiments after the flow of approximate 2.6 and 3.8∼4.1 pore volume, respectively. Until the cumulative electroosmotic flow reached to 4.5 pore volume, the treatment durations on 0.03A column experiment and 0.01 M NaOH column experiment were 38% and 23% shorter than the reference experiment, respectively.