An OMA-SIM Approach to Study OMA Kinetics for the Cleanup of Marine Oil Spill

Abstract

Breaking waves can break oil slicks into fine droplets and entrain them in the water column. An interesting hypothesis has emerged in recent years that oil droplets and mineral fines may form Oil-Mineral Aggregates (OMAs) and enhance oil dispersion in aquatic environments. The present research investigated physical processes of marine oil spills, including oil slick breakup, the formation of OMAs, and oil/OMAs vertical mixing. In this study, a modeling approach is developed for simulating the formation and vertical mixing of oil droplets and OMAs, namely Oil Droplet and OMAs Simulation (OMA-SIM). This integrated modeling tool combines the oil vertical mixing model and density-based OMAs formation model to examine the dispersion of oil droplets and OMAs. The OMA-SIM is validated using data obtained from a mesoscale wave tank experimental study. Simulation results show that the energy dissipation rate of breaking waves is the predominant factor affecting the concentration and particle size of formed oil droplets and OMAs. It also confirms that oil viscosity has a significant influence on dispersed oil concentration. High temperature, low oil viscosity, together with more formed OMAs lead to a higher concentration of dissolved oil. Other findings based on the validated OMA-SIM approach include that: the dispersants reduce oil/water interfacial tension and decrease the size of oil droplets and OMAs, and the application of mineral fines facilitates the formation of OMAs. This study indicates that the OMA-SIM is an effective modeling tool for examining the vertical dispersion of spilled oil with or without the use of dispersant and other green particle materials like mineral fines under breaking waves.