Organic fluids that do not readily dissolve in water represent a special class of environmental contamination problem. These fluids, called non-aqueous phase liquids (NAPLs) can exist in a liquid phase a gas phase, and a dissolved phase (both in water and in other organic liquids). Some organic fluids are lighter than water and called LNAPLs, and some are heavier than water and called DNAPLs. The movement of the liquid and vapor phases of the organic compound and water is complicated by their different properties including density, vapor pressure and partitioning between fluids.
PNNL has been at the forefront of multiphase research since the 1980s, starting with the U.S. Department of Energy's Subsurface Science Program and the Volatile Organic Compounds-Arid Integrated Demonstration. PNNL designed and built a state-of-the-art numerical simulator called STOMP (and its parallel implementation STOMP90) for both complex multi-fluid, multiphase calculations as well as standard flow and transport calculations. In conjunction with the simulator, PNNL designed and built an intermediate-scale laboratory facility for conducting multiphase experiments. The laboratory facilities enable us to measure sediment and organic fluid-specific properties, to understand multiphase flow phenomena and to provide test data for verifying the numerical simulator. PNNL has used these resources to help clients:
- Understand site-specific NAPL behavior
- Evaluate the effectiveness of NAPL remediation schemes, and
- Predict the long-term behavior of residual NAPL after the completion of remediation activities.