Centrifuge Testing of LNAPL Migration and Soil Vapor Extraction for Soil Remediation

Abstract

Centrifuge modeling appears to be a useful experimental tool to study geoenvironmental problems, such as pollutant migration in subsurface systems. In this paper, the migration process of light nonaqueous phase liquids (LNAPLs) in unsaturated soils and thereafter soil vapor extraction (SVE) was simulated using the geotechnical centrifuge technique. Two series of centrifuge experiments were conducted to simulate a gasoline spill from a leaking underground storage tank (UST) and the subsequent subsurface migration of the gasoline along with soil remediation techniques. When centrifuge gravity reached the desired g level, the gasoline was released from the UST. It migrated into the unsaturated soil corresponding to a prototype time equivalent to 1 year. In soil remediation tests, after the LNAPLs migration occurred for 1 year, compressed air was injected into the soil mass for periods of 2 and 4 months to extract LNAPLs into the air phase from the contaminated soil. After each centrifuge test, the soil sampl...