REMEDIATION OF PETROLEUM CONTAMINATED SOILS BY POLYMER SOLUTIONS

Abstract

This study employs computational fluid dynamics (CFD) simulations to assess the efficacy of polymer solutions in remediating petroleum-contaminated soils. Focused on the interaction between polymer solutions and soil contaminants at the Darcy scale, the research navigates through the complexities of soil pollution and the potential of polymers for environmental cleanup. Our exploration is rooted in a computational model, acknowledging its simplification of real-world dynamics yet providing pivotal insights into the remedial capabilities of polymers. In this study, computational simulations serve as a lens to examine the 'fingering effect'— a significant obstacle in the fluid dynamics of soils that complicates the process of remediation. By modifying variables like viscosity, interfacial tension (IFT), density, and injection velocity, the aim is to identify the most favorable conditions under which polymer solutions can efficiently displace Light Non-Aqueous Phase Liquids (LNAPLs). Key results demonstrate that reducing the IFT between the injected fluid and the dispelled fluid can enhance displacement efficiency by 1-2% saturation beyond baseline conditions observed in case studies. Moreover, optimizing the injected fluid's viscosity to 0.007 Pa·s markedly improves the dispelled fluid displacement, achieving a 96% effectiveness—a 6% increase compared to the case study baseline. Additionally, adjusting the injection velocity to 0.3∙ 10−4m/s further optimizes the displacement process, albeit with considerations for increased operational costs and the need for a balanced approach to achieve economic and environmental sustainability. A key discovery was that reducing the IFT between the injected and dispelled fluid enhanced the displacement efficiency of LNAPLs by an additional 1-2% saturation over baseline conditions. Furthermore, optimizing the viscosity of the injected fluid to 0.007 Pa·s significantly bolstered LNAPL displacement, achieving an unprecedented 96% effectiveness. This constitutes a 6% improvement from the baseline effectiveness observed in prior case studies. However, the study also outlines the inherent challenges and costs associated with increasing fluid viscosity, such as the need for higher injection pressure and the potential for extended project timelines.