| Summary: | 碩士 === 國立屏東科技大學 === 環境工程與科學系 === 89 === When present in aquifer in large amounts, chlorinated solvents often exist as dense non-aqueous phase liquids (DNAPL). Surfactant enhanced aquifer remediation (SEAR), also called in-situ surfactant flushing, circulates surfactants through aquifer to mobilize and/or solubilize the DNAPL. This research evaluated the influence of surfactant characteristics on the efficiency of in-situ flushing system, using PCE as an index DNAPL compound. Several biodegradable or edible surfactants were tested. The results show that, the volume of emulsified phase varied in the following order: SDS＞Tween 40＞TX-100＞Tween 80 + Span 80（4：1）＞Tween 80＞Tween60＞TX-405. Enhancement solubility of PCE is Tween 80 + Span 80＞TX-100 and Tween series＞TX-405＞SDS. Because of very little aqueous solubility, PCE recovery in column flushing test using groundwater was very low. Flushing with 1﹪Tween 80 significantly recovered PCE DNAPL. The PCE recovery is 7.08± 0.77, 7.42±1.04﹪for silica and aquifer sand, respectively, in each pore volume of flushing. Increasing numbers of flushing pore volume recovered more PCE DNAPL. The average MSR values in the flushing eluent are 5.01±1.64 for silica sand and 4.42±1.34 for the aquifer sand. Although the flow rate decreased slightly during flushing, PCE recovery still remained steady during flushing with 1﹪Tween 80. PCE recovery was increased to 10.14±2.24﹪（silica sand）and 13.05±3.54﹪（aquifer sand） in each pore volume of using co-surfactant mix of 1﹪Tween 80 + Span 80（4：1）. Such PCE recoveries are 1.5~2 fold of 1﹪Tween 80 alone. However, different to the results in 1﹪Tween 80 flushing, the flow rate during 1﹪Tween 80 + Span 80（4：1）flushing was sensitive to column.
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