Leaching Behavior of Petroleum Contaminated Soils Stabilized with High Carbon Content Fly Ash

Utilization of recycled materials as a substitute for natural soils in engineering applications such as highway construction is an emerging application area. A research study was conducted to investigate the stabilization of petroleumcontaminated soils (PCSs) using another recycled material, high carbon content fly ash (HCCFA), and evaluate the feasibility of using the final product in highway embankment construction. A battery of laboratory tests was conducted to evaluate the environmental suitability of stabilized PCSs. The test program included batch adsorption and long-term column leaching tests. Naphthalene and o-xylene, and a tertiary model non-aqueous phase liquid were used as the pollutants in batch sorption and column tests, respectively. Batch sorption tests demonstrated a nonlinear sorption behavior for naphthalene and o-xylene onto HCCFA. Column leaching test results indicated that the naphthalene and o-xylene concentrations in the effluents collected from the stabilized PCSs columns were lower than those collected from the control columns. These laboratory test data suggest that HCCFA can be effective in remediation of PCSs; however, the level of petroleum contamination has a significant effect on the leaching properties.