CAREER: Coupled Phenomena Resilience and Dynamics in Bentonite Barriers

Villanova University, Villanova PA

Investigators

Abstract

This Faculty Early Career Development (CAREER) award will address national and global challenges of water security, environmental protection, and preparation of future STEM professionals. The research focuses on transforming how we measure, predict, and educate others about the long-term performance of clay barriers used for environmental protection. Engineered clay barriers, particularly those utilizing bentonite clay, are commonly used to protect communities and their water resources from pollutants from industrial, municipal, and radioactive wastes. Sustaining performance of protective barriers over time within evolving geoenvironments is critical to preserving national water quality and public health. However, variable chemical, temperature, hydraulic, and stress conditions that occur in bentonite in the field have complex, coupled effects on the rate of contaminant transport through the barrier. Until recently, research on these coupled phenomena has primarily focused on overly-simplified conditions that do not represent the real-world dynamics of clay barriers exposed to wastes. This research includes comprehensive experimental and analytical evaluation of coupled contaminant transport properties of bentonite barriers under more realistic conditions. The results will improve prediction and modeling of how contaminants escape through clay barriers over time, supporting design of resilient barrier systems and improved protection of public health and the environment. The integrated education and research objectives include research experiences for undergraduate students, middle and high school STEM outreach that broadens participation in engineering, and development of an activity library to advance geoenvironmental engineering education. The goal of this research is to advance scientific understanding of how environmental dynamics and coupled phenomena impact long-term resiliency of bentonite-based containment barriers. The project includes advanced experimental measurements of coupled transport properties of bentonites under changing chemical, temperature, hydraulic, and stress conditions for both virgin and field-exhumed samples. The objectives of the integrated research and education plan include: (i) measurement of coupled phenomena and chemical transport properties of traditional and polymer-enhanced bentonites; (ii) improved modelling of coupled mass flux through clays; (iii) undergraduate involvement through mentored research experiences; and (iv) development of a digital activity library to enhance geoenvironmental engineering education. The results will answer fundamental questions about how barrier performance is impacted by evolving chemical-hydraulic-thermal-stress conditions, field exposure, and material enhancement. This project will allow the PI to advance the knowledge base in geotechnical, environmental and water resources engineering, as well as clay science, and support her long-term career in innovative geoenvironmental research. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.