RECOVERY OF OILY COMPONENTS FROM MIXED THREE PHASE SYSTEM : in situ WASHING WITH MILDLY CONCENTRATED SURFACTANT SOLUTIONS

Cho, Daechul; Kwon, Sung Hyun

Environmental Engineering Research 2001;6(4): 223-232.

Daechul Cho¹^†, and Sung Hyun Kwon²

¹Environmental Engineering, Division of Materials and Chemical Engineering, Soonchunhyang University, Asan 336-745, Korea
²Department Marine Environmental Engineering, Institute of Marine Industry, Kyeongsang National University, Tongyong 650-160, Korea

Corresponding Author: Daechul Cho ,Tel: +82-41-530-1341, Fax: +82-41-530-1358, Email: daechul@sch.ac.kr

Received: April 17, 2001; Accepted: September 18, 2001.

ABSTRACT

Surfactant soil flushing was conducted to investigate the effects of porosity of soil matrix, residence time of flushing, and degree of solubilization(involving mobilization) in a hydrocarbon contaminated soil column bed in an in situ-]ke fashion. Two model surfactant solutions, sodium dodecyl sulfate (SDS) and polyoxyethylene (20) sorbitan monooleate (Tween-80) were used as flushing agent. Sand and kaolin were two selected soil components. Tween-80, a nonionic surfactant, showed a better cleaning performance per micelle or molecule than SDS by order of magnitude of 2 probably because of the larger aggregation number or bulkiness of the micelles. Hydrocarbon removal efficiency increased with higher concentration of surfactant solution, higher retention time through the bed, and smaller porosity of the soil matrix. Batchwise injection of the surfactant solutions led to higher removal efficiency than continuous injection regardless retention time, which implies that the rate-controlled solubilization(mobilization) step might be better controlled by intermittent surfactant injection.

Keywords: hydrocarbon oil | intermittent flushing | soil flushing | solubilization | surfactant